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Household running costs questions, answered
Electricity and heating, water, appliances, a pool, solar and insulation, and what each thing costs to keep going.
Every answer below is taken from the calculator or guide that works the number out, and each heading links back to it so you can put your own figures in. Nothing here is advice, and where a rate or threshold applies the page that owns the answer holds the current figure.
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Cost Of A Bad Hire Calculator NZ 2026/27
How much does a bad hire cost?
On the worked example, $139,157.67 for someone on an $82,000.00 salary who lasted seven months. That is 1.70 times their annual salary and 75.22% of the business's $185,000.00 annual profit. The salary itself is only $47,833.33 of it. The rest is recruitment already spent, training, management time, lost customer revenue, rework, the effect on colleagues and the cost of exiting them.
Why is a bad hire more expensive than the salary?
Because the salary is the one part you were always going to pay. Everything else is loss. On the worked example the salary and employer costs over seven months come to $51,707.83, while the other components total $87,449.83: $14,189.00 of recruitment that bought nothing, $6,500.00 of training that walked out the door, $3,990.00 of management time, $38,000.00 of damaged customer revenue, $9,500.00 of rework, $8,437.50 of disruption to colleagues and $6,833.33 to exit them.
How does a bad hire affect the rest of the team?
They absorb the work that is not being done and the work that has to be redone, and they spend time supporting someone who is struggling. On the worked example, three colleagues losing 15% of their productivity for three months costs $8,437.50. That is a conservative estimate and it excludes the harder effect, which is the message sent to good performers when underperformance is tolerated for months.
Do 90-day trial periods reduce the cost of a bad hire?
They can substantially, because most of the cost accumulates with time. On the worked example, ending the employment at three months rather than seven would have avoided roughly $29,547.33 of salary and employer costs alone, before counting the additional customer damage, rework and disruption those extra four months produced. Trial provisions have specific requirements about how the agreement is written and when it is signed, and getting those wrong removes the protection entirely, so take advice rather than relying on a template.
What is the biggest cost in a bad hire?
Usually the customer damage, and it is also the least visible. On the worked example, $38,000.00 of lost or damaged customer revenue is the single largest line, ahead of the $47,833.33 of salary only because the salary spans seven months. Customer effects are hard to estimate and easy to leave at zero, which is exactly why bad hires are systematically underpriced by the businesses that suffer them.
How can I avoid making a bad hire?
Spend more on the front end, because the arithmetic is heavily in favour of it. On the worked example a single bad hire costs $139,157.67, which is nearly ten times the $14,189.00 cost of a full agency-supported search. Structured interviews with the same questions for every candidate, a practical work sample, and genuinely completed reference checks all cost hours rather than thousands. The most expensive recruitment decision is almost always hiring someone adequate quickly because the role has been open too long.
Should I keep a bad hire while I look for a replacement?
It depends on whether they are net positive or net negative, which this page helps quantify. Someone who is simply slow may be better than nobody. Someone damaging customer relationships or creating rework is costing more each month than an empty seat would. On the worked example the customer and rework costs alone are $47,500.00 over seven months, which is $6,785.71 a month of pure loss. Any decision here has process obligations attached, so take employment advice first.
Is a bad hire always the employee's fault?
Frequently not, and treating it that way guarantees a repeat. Common causes sit with the business: an unclear role, no proper onboarding, a manager with no time to supervise, or a decision made in haste because the vacancy was hurting. Before recruiting a replacement it is worth asking honestly which of those applied, because hiring a second person into the same conditions tends to produce the same result and the same bill.
NZ Electricity Cost Calculator 2026
What is the average electricity price in New Zealand?
The national average residential electricity price in New Zealand is 39.3 cents per kWh (including GST), based on the MBIE Quarterly Survey of Domestic Electricity Prices (QSDEP) as at February 2026. Prices vary significantly by region, from 34.61c/kWh in Wellington (the cheapest) to 48.93c/kWh in Balclutha (the most expensive). The average NZ household uses approximately 8,000 kWh per year (about 22 kWh per day).
How much does the average NZ household spend on electricity per month?
At the national average rate of 39.3c/kWh and average consumption of 8,000 kWh per year, the typical NZ household spends approximately $262 per month on electricity usage alone. Adding a typical daily fixed charge of $1.00 to $2.00 per day brings the total bill to roughly $290 to $320 per month. This varies significantly based on your region, household size, heating method, and hot water system. Households with heat pumps and electric hot water typically use more electricity than those with gas heating and gas hot water.
Why does electricity cost more in some NZ regions?
Regional price differences are primarily driven by lines charges (the cost of distributing electricity to your home), which account for roughly one-third of your power bill. Rural and remote areas have higher lines charges because the infrastructure must cover longer distances and serve fewer customers. The energy generation component is relatively similar nationwide, but local network costs, terrain, and population density create significant variation. You cannot choose your lines company as it is determined by your address.
How much electricity does a heat pump use?
A typical residential heat pump uses approximately 1,500 watts (1.5 kW). Running it for 6 hours per day during winter at the national average rate of 39.3c/kWh costs about $3.54 per day, or approximately $106 per month. Heat pumps are significantly more efficient than electric fan heaters (2,000W) or oil column heaters (2,400W) because they move heat rather than generate it, delivering 3 to 4 units of heat for every 1 unit of electricity consumed.
How much does it cost to charge an electric vehicle at home in NZ?
A typical home EV charger draws approximately 7 kW. Charging for 3 hours per day (enough for average daily driving of about 40-50 km) at the national average rate of 39.3c/kWh costs approximately $8.25 per day or $248 per month. Charging overnight on an off-peak tariff can reduce this cost significantly. Even at standard rates, home EV charging is substantially cheaper than petrol for equivalent distance.
NZ Rates and Water Calculator 2026
How much are council rates in NZ?
Council rates in New Zealand typically range from 0.2% to 0.6% of your property's capital value per year. A property valued at $700,000 might pay $2,000 to $4,000 in annual rates depending on the council. Rates vary significantly between councils and are set annually. They cover services like roading, water, wastewater, stormwater, parks, libraries, and rubbish collection.
What do council rates cover?
Council rates fund local government services including road maintenance, water supply, wastewater treatment, stormwater drainage, parks and reserves, libraries, community facilities, rubbish and recycling collection, resource management, building inspection, and emergency management. The exact services and costs vary by council.
How are council rates calculated?
Most NZ councils calculate rates based on your property's capital value (CV) or land value (LV) from the most recent council valuation. A rate in the dollar is applied to this value. There may be a uniform annual general charge (UAGC) which is a flat fee per property, plus targeted rates for specific services like water, wastewater, and rubbish. Some councils use a mix of capital value and land value rating.
How are water charges calculated in NZ?
Water charges vary by council. Some councils include water in general rates. Others charge volumetrically based on metered usage (typically $1.50 to $3.50 per cubic metre). Some charge a targeted rate (flat annual fee per property). Auckland charges $1.77 per cubic metre for water supply and $3.25 per cubic metre for wastewater (based on winter usage). Christchurch does not meter residential water and includes it in rates.
Can I get a rates rebate?
Yes. The Rates Rebate Scheme helps low-income homeowners with their rates. For the 2026/27 rating year (1 July 2026 to 30 June 2027) the maximum rebate is $830 per year. You get the maximum if your household income is $33,210 or less, or $46,400 or less if you hold a SuperGold card, with an extra $500 of income allowed for each dependant. Households above those thresholds may still get a reduced rebate. Apply through your local council by 30 June 2027. You must own and live in the property.
Are Solar Panels Worth It Guide
Are solar panels worth it in New Zealand?
It depends on your power use, roof and how much electricity you use during daylight. The payback is best for households that use a lot of power in the day.
How long do solar panels take to pay back?
Often around 6 to 12 years depending on system size, cost, your usage and the buy-back rate, after which the power is effectively free.
Do I need a battery with solar panels?
No. A battery lets you store daytime generation for night use but adds significant cost, so many households start without one.
What is a solar buy-back rate?
The rate your power company pays for excess electricity you export to the grid, usually well below the retail price you pay, so using your own power is more valuable.
Pool Salt Calculator NZ
How much salt does a salt water pool need?
Most residential salt chlorinators in New Zealand run between 3,000 and 4,000 ppm. Hayward, Pentair and Jandy all nominate 3,200 ppm as the optimum. For a 46,400 litre pool starting from fresh water, reaching 3,200 ppm takes about 148 kg of salt, which is eight 20 kg bags.
Can I put too much salt in a pool?
Yes. High salinity can corrode the chlorinator cell and pool fittings, and salt cannot be filtered or chemically removed. The only way to lower it is to drain part of the pool and refill with fresh water, so it is better to add salt in stages and retest.
How long does pool salt take to dissolve?
Around 24 hours with the pump running. Brush it across the floor rather than leaving it piled up, and do not test the salinity until it has fully dissolved or the reading will be low and you will overdose.
Do I need to add salt every year?
Not usually. Salt is not used up by the chlorinator and does not evaporate with the water. You only replace what is lost through backwashing, splash-out and overflow, which is normally a bag or two a season rather than a full dose.
Pool Volume Calculator NZ
How many litres is a standard New Zealand backyard pool?
Most residential pools in New Zealand hold between 20,000 and 60,000 litres. A common 8 m by 4 m pool with a floor sloping from 1.1 m to 1.8 m holds about 46,400 litres. Small plunge pools can be under 10,000 litres.
Do I measure the pool inside the walls or outside?
Measure the water, not the structure. Use the internal dimensions at the waterline, since that is the space the water actually occupies. Measuring the outside of the coping will overstate the volume.
How do I work out the volume if my pool is an odd shape?
Split it into shapes you can measure. Work out the volume of each part separately and add them together. A kidney shape is usually close enough to an oval for dosing purposes.
Why does pool volume matter for chemicals?
Every pool chemical is dosed per thousand litres of water. If your volume estimate is 20 per cent low, every dose you add is 20 per cent short, and the chlorine or salt level never reaches where it needs to be no matter how much you keep adding.
Appliance Running Cost Calculator NZ
How do I work out an appliance running cost?
Multiply the appliance power in kilowatts by the hours you use it to get the energy used, then multiply by your power price. This calculator does it for the cost per hour, week and year.
How do I find an appliance wattage?
It is usually on a label on the appliance or in the manual, in watts. Divide watts by 1000 to get kilowatts. Heaters and dryers draw a lot; small electronics draw little.
Which appliances cost the most to run?
High-wattage appliances used for long periods, like heaters, dryers and old fridges, cost the most. Working out the cost helps you decide what to use less or replace.
Coffee to Water Ratio Calculator
What is the best coffee to water ratio?
The Specialty Coffee Association (SCA) recommends a golden ratio of approximately 1:18 (about 55 grams of coffee per litre of water). Most specialty coffee drinkers use ratios between 1:15 (strong) and 1:18 (light). The ideal ratio depends on your brew method and personal taste: espresso uses 1:2, French press typically uses 1:15, pour over 1:16 to 1:17, and cold brew 1:8.
How many grams of coffee do I need for 250 mL of water?
At a 1:16 ratio, 250 mL of water requires 250 / 16 = 15.6 grams of coffee. At 1:15 (stronger) you need 16.7 grams, and at 1:17 (lighter) you need 14.7 grams. Since water weighs 1 gram per millilitre, 250 mL of water weighs 250 grams. Simply divide the water weight in grams by your chosen ratio to get the coffee dose.
How do I measure coffee to water ratio without a scale?
A digital kitchen scale is strongly recommended for accurate coffee ratios. Without one, a rough guide is: 1 tablespoon of ground coffee weighs approximately 5 to 7 grams (depending on grind size and coffee density). For a standard 250 mL cup at 1:16, you would need about 2 to 3 tablespoons. Volume measurements are much less accurate than weight, so using grams gives more consistent results.
Cost of a Deck or Fence All-In Calculator NZ 2026
How much does a deck cost in New Zealand?
A ground-level timber deck in New Zealand typically costs $800 to $1,400 per square metre all-in (materials plus labour plus GST). Composite decking runs $1,200 to $2,000 per square metre. Elevated decks (over 1.5 m) cost more due to structural piles and bracing, often adding $300 to $700 per square metre. A typical 20 m2 ground-level pine deck might cost $16,000 to $28,000 fully installed in 2026. Consent is required if the deck is more than 1.5 m above the ground or over 20 m2 in some councils.
How much does a fence cost in New Zealand?
Fencing in New Zealand costs roughly $150 to $450 per linear metre installed, depending on material and height. A standard 1.8 m timber paling fence runs about $180 to $280 per metre. A Colorsteel or corrugated iron fence costs $200 to $350 per metre. Horizontal cedar slat fencing, popular for its modern look, costs $280 to $450 per metre. Chain-link or wire fencing is the most affordable at $80 to $150 per metre. These prices include posts, rails, palings or panels, concrete, and labour.
Do I need a building consent for a deck or fence in New Zealand?
Under the Building Act 2004, a deck does not require a building consent if it is no more than 1.5 m above the ground at any point and is no larger than 20 m2 (for single-storey dwellings). If your deck exceeds either threshold, a consent is required and will typically cost $1,500 to $3,000 through your local council. Fences generally do not require building consent unless they exceed 2.5 m in height. Retaining walls over 1.5 m do require consent. Always check with your local council as district plans and heritage overlays may add restrictions.
Cost of BNPL Defaults Calculator NZ
How much are BNPL late fees in New Zealand?
It varies by provider. Afterpay charges an initial late fee and a further fee if still unpaid, capped at the lesser of 25 percent of the order or a set dollar amount. Laybuy and Zip have their own fees. Enter your provider's fees to see the total.
Is there a cap on BNPL late fees?
Most providers cap total late fees on a single order, often at 25 percent of the purchase price or a fixed dollar amount, whichever is lower. The calculator applies a cap so you see the most you could be charged.
Why are missed BNPL payments expensive?
Because the fees are a large share of a small purchase. A few dollars of late fees on a 50 dollar order can be a 20 to 40 percent surcharge, far higher than typical credit interest over the same short period.
Cost of Minimum Card Payments Calculator NZ
Why do minimum payments cost so much?
The minimum is usually only 2 to 3 percent of the balance, so most of it goes on interest and the balance barely moves. At typical credit card rates a balance can take well over a decade to clear and cost more in interest than the original debt.
What is the minimum payment on an NZ credit card?
Most New Zealand cards set the minimum at the greater of around 2 to 3 percent of the balance or a small dollar floor such as 10 or 20 dollars. Enter your card's terms to match it.
How do I get out of the trap?
Pay a fixed amount above the minimum each month, or move the balance to a lower-rate product. Even a small fixed payment dramatically cuts the time and interest, because more goes to the principal each month.
Cost of Owning a Pool Calculator NZ 2026
How much does it cost to own a pool per year in New Zealand?
For a medium inground concrete pool, typical annual running costs in New Zealand range from $2,500 to $5,000. This includes chemicals ($800 to $1,500), pump electricity ($600 to $1,200), regular maintenance ($400 to $800), and an insurance premium increase ($200 to $400). Heating adds significantly more if used: gas heating can cost $1,500 to $4,000 per year, while a heat pump is cheaper to run at $500 to $1,500 per year.
How much does it cost to install a pool in NZ?
In 2026, installing an inground concrete pool in New Zealand typically costs between $35,000 and $80,000 depending on size, shape, and site conditions. Fibreglass pools are generally cheaper to install at $25,000 to $55,000. Above-ground pools start from around $3,000 to $15,000. Additional costs include fencing (mandatory in NZ), a pool cover, heating, lighting, and council consent fees.
Does a pool add value to a NZ home?
In New Zealand, a pool generally adds less value to a property than it costs to install. Most valuers estimate a pool adds 3 to 7 percent to a home's value, which on a $900,000 home is $27,000 to $63,000. If the pool cost $50,000 to install, you may not fully recover the investment. Pools can also deter some buyers who do not want the ongoing maintenance costs. The value added depends heavily on the suburb, climate, and the quality of the pool.
Cost of Raising a Child Calculator NZ 2026
How much does it cost to raise a child in NZ?
Estimates range from around $150,000 to over $300,000 to age 18, depending on income, childcare and lifestyle. Your own figure depends on your weekly spend, which is why this calculator builds the total from your numbers rather than a single average.
Does this include government support?
No, it estimates your gross spending. Working for Families tax credits, Best Start payments and childcare subsidies can offset a significant part of the cost, so calculate your entitlement to those separately and subtract them for a net figure.
Why use a weekly average?
Costs change as children grow, with childcare heavy in the early years and food, activities and technology later. A weekly average across all the years smooths this out and gives a realistic lifetime total without needing a year-by-year breakdown.
Cost of Raising a Child to 18 Calculator NZ 2026
How much does it cost to raise a child in New Zealand?
Research by Massey University and the New Zealand Council for Educational Research suggests the total cost of raising a child to age 18 in New Zealand ranges from approximately $260,000 for lower-income households to over $400,000 for higher-income households, in today's dollars. A middle-income household in a main urban area typically spends around $310,000 to $340,000. These figures include childcare, primary and secondary schooling, food, clothing, healthcare, transport, housing costs attributable to the child, and recreational activities.
What are the biggest costs in raising a child in NZ?
For families who use full-time early childhood education (ECE), childcare is typically the largest single cost in the first five years, with fees ranging from $200 to $500 per week above the 20-hour funded entitlement (for under-twos). Beyond the early years, the largest ongoing costs are food (roughly $100 to $200 per week for a child's share of the household food budget by teenage years), housing (the additional space a child requires), transport, and school costs including uniforms, stationery, camps and device levies. Extracurricular activities such as sport, music and cultural programmes add significantly for many families.
What government support is available to help with the cost of raising children in NZ?
New Zealand offers several government programmes. Working for Families tax credits (including the Family Tax Credit, In-Work Tax Credit, and Best Start payment) provide regular payments to eligible low- and middle-income families. The Best Start payment of $3,310 per year is available for all families in the first year after birth, and for families earning under $93,858 until the child turns three. Twenty hours per week of free early childhood education (ECE) is funded by the government for all children aged three and four. The Accommodation Supplement helps with housing costs. Childcare Assistance provides additional childcare subsidies for low-income families. Prescription and GP costs for under-14s are funded by the government.
Cost of Waiting to Buy Calculator NZ
Does waiting to buy a house save money?
It can if you save a much bigger deposit and prices stay flat, but if prices rise while you wait, the home costs more and you need a larger deposit to match, which can wipe out the benefit. This calculator weighs both effects.
Should I wait for a bigger deposit?
A bigger deposit lowers your loan and may avoid low-equity costs, but waiting risks prices rising faster than you save. The right call depends on how fast you can save versus how fast prices and rates move.
Can anyone predict house prices?
No. This tool uses your assumptions about price growth to show the trade-off, not a forecast. Try a range of growth rates to see how sensitive the decision is before you commit either way.
Dehumidifier Running Cost Calculator NZ
How much does a dehumidifier cost to run?
It depends on its power rating (often 200 to 700 watts), how long it runs, and your power price. Run for a few hours a day over winter, a typical dehumidifier might cost a few dollars a week, which adds up across the colder months.
Is a dehumidifier cheaper than heating?
A dehumidifier uses far less power than most heaters, and a drier home is easier and cheaper to heat. Running one to control damp can reduce both heating costs and the health problems that come with a damp home.
How can I reduce the cost?
Use the humidistat so it only runs when needed, run it in a closed room, and fix the sources of moisture (ventilation, drying washing outside). A more efficient model also uses less power for the same result.
Firewood Calculator NZ
How much firewood do I need for winter?
It depends on how often you burn and for how long. Many households use a few cubic metres a season. This calculator estimates your seasonal volume from how often you light the fire.
How is firewood sold in New Zealand?
Often by the cubic metre, sometimes thrown or stacked, which can differ. Compare suppliers on a consistent measure, and buy dry, seasoned wood, which burns far better than green wood.
Why does dry firewood matter?
Dry, seasoned wood produces more heat and less smoke than wet or green wood, so it is better value and better for air quality. Buying ahead and storing it under cover helps.
Firewood vs Heat Pump Calculator NZ
Is a wood burner or heat pump cheaper to run?
It depends on firewood and power prices in your area. Heat pumps are very efficient, delivering several units of heat per unit of power, while a wood burner's cost depends on what you pay for firewood. Cheap or free wood can make a burner cheaper; bought firewood is often comparable to a heat pump.
How do I compare firewood and heat pump costs?
Work out the cost to deliver the same heat each way: firewood by the cord allowing for the burner's efficiency, and the heat pump by the power it uses, helped by its high efficiency. This calculator does both for a season.
What else matters besides cost?
Wood burners give a strong, cosy heat and work in a power cut, but need wood handling and meet clean-air rules in some areas. Heat pumps are easy and also cool in summer. Cost is one part of the choice.
Healthy Homes Heating Capacity Calculator NZ
What does the Healthy Homes heating standard require?
Rental properties must have a fixed heater in the main living room that can heat it to at least 18 degrees. The required capacity is set by an official formula based on the room size, its windows and insulation, and the local climate.
How is the required capacity worked out?
It depends on the room volume, how well the room is insulated and how cold your region gets. Bigger, draughtier rooms in colder areas need more kilowatts. This tool gives an estimate; the official Tenancy Services heating tool gives the compliant figure for a tenancy.
Does a heat pump count?
Yes, a fixed heat pump of sufficient capacity is one acceptable option, as are some other fixed heaters. The heater must meet the required capacity for the room. Portable heaters and unflued gas heaters do not qualify.
Heat Pump vs Wood vs Pellet Heating Cost Calculator NZ
What is the cheapest way to heat a home in New Zealand?
For most homes a modern heat pump is the cheapest to run, because it delivers several units of heat per unit of electricity. Wood can be competitive where firewood is cheap or free, while pellets offer convenience. This calculator compares all three using your own fuel prices.
What is a coefficient of performance (COP)?
The COP measures a heat pump's efficiency: a COP of 4 means it delivers four units of heat for every unit of electricity it uses. A higher COP means lower running costs. Real-world COP varies with temperature, so use a realistic average for your climate.
Does this include the purchase price?
No, it compares running cost only. A heat pump or pellet fire costs more to buy and install than a basic wood burner, so weigh the ongoing fuel savings shown here against the upfront cost, along with convenience, maintenance and how well each heats your space.
Home Heating Cost Calculator NZ
What is the cheapest way to heat a home in New Zealand?
A modern heat pump is usually the cheapest to run, because it moves several units of heat for each unit of electricity. A plug-in electric heater gives one unit of heat per unit of power, so it costs several times more for the same warmth.
Why is a heat pump cheaper than an electric heater?
A heat pump has a coefficient of performance, often around 3 to 4, meaning it delivers 3 to 4 units of heat per unit of electricity. A resistance heater has a coefficient of 1, so it uses far more power for the same heat.
How much does it cost to run a heater?
It depends on the heat output, the hours used, your power price and the efficiency of the heater. This calculator estimates the cost per hour and per season for the options you compare.
Hot Water Cost Calculator NZ
How much does hot water cost in New Zealand?
Hot water is often around a third of a power bill. The cost depends on how many people use it, the water heating type, and your power price. This calculator estimates the annual cost for your household.
How can I cut hot water costs?
Shorter showers, an efficient shower head, fixing drips, and an efficient cylinder such as a heat pump water heater all help. A heat pump cylinder uses far less power than a standard electric one.
Is a heat pump water heater worth it?
A heat pump cylinder can deliver hot water using a fraction of the electricity of a standard element, so it can cut hot water costs substantially, though it costs more to install.
Insulation Calculator NZ
How much insulation do I need?
Work out the area of the ceiling, wall, or floor to insulate, then divide by the coverage of one pack. The calculator does this and rounds up to whole packs. Coverage is printed on the pack and varies with the segment width and R-value.
What R-value do I need in New Zealand?
The Building Code sets minimum R-values that vary by climate zone and by whether it is a ceiling, wall, or floor. Ceilings need the highest. Check the current requirements for your area and choose a product that meets or beats them.
Should I allow for framing?
Insulation fits between the framing, so the actual segment area is a little less than the gross area. Buying to the gross area gives a small safety margin and covers offcuts, which is sensible.
Pool Build Cost Calculator NZ 2026
How much does a pool cost to build in NZ?
An in-ground fibreglass pool commonly starts around $40,000 to $70,000 installed, and a concrete pool more, before fencing, landscaping and plant. Once those are included the all-in cost is often well over $80,000, which is why budgeting extras and a contingency matters.
Is fibreglass or concrete cheaper?
Fibreglass is usually cheaper and faster because the shell is made off site and craned in, while concrete costs more but can be any shape or size and is very durable. This calculator lets you compare the two by switching the pool type.
Do I have to fence a pool in New Zealand?
Yes. Pools capable of holding more than 400mm of water generally require compliant fencing under New Zealand law, and councils inspect for it. Always include fencing in your budget, as it is both a legal requirement and a real cost.
Cost of Owning a Pool Calculator NZ 2026
How much does a pool cost to run per year in NZ?
Many home pools cost roughly $1,500 to $3,000 a year to run once power, chemicals, water, servicing and insurance are added, with heating the biggest variable. A heated pool can cost considerably more, while an unheated, covered pool is at the lower end.
What is the biggest running cost of a pool?
Electricity is usually the largest cost, mostly the filtration pump and any heating. Running the pump on a timer for only the hours needed, and using a heat pump rather than electric resistance heating, are the most effective ways to cut it.
Does a pool cover save money?
Yes. A fitted cover sharply reduces evaporation, heat loss and chemical use, cutting power, water and chemical costs. Covers usually pay for themselves within a couple of seasons, especially on a heated pool, and they also improve safety and cleanliness.
Pool Running Cost Calculator NZ
How much does a pool cost to run a year?
Running costs come from the pump power, chemicals, water top-ups and any heating, plus servicing. A pool without heating might cost a few hundred to over a thousand dollars a year, while a heated pool can cost much more, driven mostly by the heating energy.
What is the biggest cost of owning a pool?
For a heated pool, heating is usually the largest cost by far. For an unheated pool, the pump running for hours each day to filter the water is the main electricity cost, alongside chemicals.
How can I cut pool running costs?
A pool cover reduces heat loss and evaporation, an efficient or variable-speed pump cuts power, and running the pump only as long as needed all help. Heating is the area where savings make the biggest difference.
Pooled Standard Deviation Calculator
What is pooled standard deviation?
It is a single estimate of variability that combines two groups' variances, weighting each by its degrees of freedom. It assumes the groups share a common underlying spread, and it is used in the two-sample t-test and effect-size measures like Cohen's d.
When should I pool standard deviations?
Pool when you can reasonably assume the two groups have similar true variances. If their sample standard deviations are close, pooling is sound. When the variances clearly differ, methods that do not pool, such as Welch's t-test, are more appropriate.
How is it different from averaging the two SDs?
It is a weighted combination of the variances, not a simple average of the standard deviations. Each variance is weighted by its degrees of freedom, so the larger sample has more influence, and the result is taken as a square root, which gives a statistically sound common estimate.
Power Bill Estimator NZ
How do I estimate my power bill?
Multiply your average daily usage in kilowatt hours by the number of days and by your unit price, then add the daily fixed charge times the number of days. This calculator does both parts for you and projects the total across a year for budgeting.
What is the daily fixed charge?
It is a set amount you pay each day simply to stay connected to the network, regardless of how much electricity you use. Low-user plans have a small fixed charge but a higher unit price, which can suit households that use little power.
Where do I find my usage and unit price?
Both appear on a recent power bill, and most providers show daily usage in their app or online account. Use your average daily kilowatt hours and the unit price in cents per kilowatt hour to get the most accurate estimate from this tool.
Roof Water Catchment Calculator NZ 2026
How much rainwater can I collect from my roof?
Each millimetre of rain on a square metre of roof yields one litre. So a 120 square metre roof in a 1,200mm rainfall area can collect well over 100,000 litres a year at typical efficiency. This calculator works it out from your roof size, rainfall and efficiency.
Do I use the roof footprint or the sloped area?
Use the footprint, the area seen from directly above, because rain falls vertically. The sloped surface is larger but collects the same rain as its footprint, so using the sloped area overstates the catchment.
Why is collection efficiency less than 100 percent?
Some water is lost to the first flush that cleans the roof, to splashing and overflow during heavy rain, and to evaporation. A realistic efficiency is around 75 to 90 percent, so the usable catchment is a little less than the theoretical maximum.
Room Heat Pump Sizing Calculator NZ
What size heat pump do I need for a room?
As a rough guide a well insulated New Zealand room needs around 40 to 60 watts of heating per cubic metre of space, rising to 70 to 80 watts for poorly insulated or colder rooms. Multiply your room volume by that figure to get the heating capacity in watts, then divide by 1,000 for kilowatts. This calculator does that and rounds up to a common model size.
Is it better to oversize or undersize a heat pump?
A slightly oversized heat pump that comfortably meets the load on the coldest days is usually better than one that is undersized and runs flat out without keeping up. A very oversized unit can short cycle and cost more to buy. Aim for a capacity a little above your calculated heating load, which is what the suggested model size here does.
Does insulation change the heat pump size?
Yes, a lot. A well insulated room with good curtains and double glazing can need close to half the heating capacity of a poorly insulated room of the same size. Improving ceiling and underfloor insulation first can let you fit a smaller, cheaper and more efficient heat pump.
Second Fridge Cost Calculator NZ
How much does a second fridge cost to run?
An old second fridge or freezer can use several hundred kWh a year, costing anywhere from around $100 to $300 or more in power. Older units are far less efficient than modern ones, so the cost is often higher than people expect.
Is it worth keeping an old garage fridge?
If it only holds a few drinks, the yearly running cost can be poor value. Switching it off, or replacing an old unit with an efficient one if you need the space, can pay for itself over a few years in power saved.
How do I find my fridge's energy use?
The energy rating label or manual gives a kWh per year figure for newer units. For an old fridge with no label, you can estimate, or use a plug-in power meter to measure it, then enter the figure here.
Solar Battery Payback Calculator NZ
Is a home battery worth it with solar?
A battery lets you use more of your own solar power in the evening instead of buying from the grid, and avoids exporting it for a low buy-back rate. The saving is the gap between the retail power price and the export rate, on the energy you shift, weighed against the battery cost.
How is the battery saving calculated?
It is the energy the battery lets you self-use each year, multiplied by the difference between what you would pay to buy power and what you would get for exporting it. The bigger that gap, the faster the battery pays back.
Do batteries last long enough to pay back?
Batteries are warrantied for around 10 years. If the payback is well under that, it stacks up; if it is close to or beyond the battery life, the economics are marginal, though backup power has value in outages.
Solar Panel Count by kW Calculator
How many solar panels do I need for a 6 kW system?
At 400 W per panel, a 6 kW system requires 15 panels (6,000 W divided by 400 W). At 350 W per panel, you would need 18 panels (rounding up from 17.14). The exact count depends on the wattage rating of the panels you choose. Higher-wattage panels (such as 430 W or 450 W) mean fewer panels for the same system size, which reduces the roof area needed.
How much roof area does a solar system need in New Zealand?
A standard 400 W solar panel is approximately 1.7 m x 1.0 m, giving a panel area of around 1.7 m2. A 6 kW system using fifteen 400 W panels therefore requires roughly 25.5 m2 of usable, unshaded north-facing roof space. In practice you should allow a little extra clearance between panels for airflow and mounting, so plan for around 30 m2 of total roof area for a system of this size.
What are typical peak sun hours in New Zealand?
Peak sun hours measure the equivalent number of hours per day that solar irradiance averages 1,000 W per square metre. In New Zealand, annual averages range from about 3.5 peak sun hours per day in Southland to 4.8 in Nelson and Marlborough, with Auckland around 4.2, Wellington around 4.0, and Christchurch around 4.5. These figures are annual daily averages; summer values are higher and winter values lower. Installers use these figures to estimate annual energy yield when sizing a system.
Solar Panel Calculator NZ 2026
How many solar panels does a NZ house need?
It depends on your power use and target offset. A typical home using 8,000 kilowatt-hours a year and covering most of it needs roughly a 6 kilowatt system, about 14 to 16 modern panels. This calculator sizes it from your own usage and panel wattage.
How much roof do I need for solar?
Allow roughly 2 square metres per panel, so a 15 panel system needs around 29 square metres of unshaded, ideally north-facing roof. Orientation and shading matter a lot, so a site assessment from an installer will confirm what your roof can fit.
Should I size solar to cover all my power?
Not usually. Covering 100 percent means exporting a lot of cheap midday power and paying retail in the evenings. Many households size for 70 to 90 percent of use, and add a battery or shift appliance use to midday to lift how much of their own solar they consume.
Solar Panel Payback Calculator NZ
How long does solar take to pay for itself in New Zealand?
It depends on the system cost, how much power it generates, how much you use yourself versus export, and your tariffs. Many systems pay back over several years; this calculator estimates the period for your situation.
Is it better to use solar power or export it?
Power you use yourself saves the full retail price, while exported power earns a usually lower buy-back rate. So the more of your generation you use directly, the faster solar pays back.
What affects solar savings?
System size and cost, your location and sunshine, how much you self-consume, your power price and the export rate all matter. Use realistic figures, as optimistic sales estimates can overstate the savings.
Spa Pool Running Cost Calculator NZ
How much does a spa pool cost to run?
Most of the cost is electricity to keep the water hot, which depends on the spa's insulation, your climate and how often you use it, plus chemicals and water. A typical spa might cost a few hundred to over a thousand dollars a year to run.
What is the biggest spa cost?
Heating. Keeping the water hot around the clock, or reheating it for each use, is the main electricity cost. A good cover and insulation, and turning the temperature down between uses, cut this significantly.
How can I run a spa more cheaply?
Use a well-fitting insulated cover, keep the spa at a lower temperature when not in use, run the pump only as needed, and consider an off-peak power plan. Heating is where the savings are largest.
Stock Water Requirements Calculator NZ
How much water does a dairy cow drink a day in New Zealand?
A lactating dairy cow needs more than 100 litres a day in summer, and drinks it in two to six visits rather than steadily through the day, which is why trough flow rate matters as much as total volume. DairyNZ recommends sizing reticulation to deliver about 20 litres per cow per hour. Demand falls in winter and rises sharply in hot dry weather.
How many days of stock water storage should I have?
Two to three days is a common minimum so that a pump failure, a power cut or a burst line does not become an animal welfare problem before it is found. Blocks on a bore or a stream take with no alternative supply often carry more. The right number depends on how quickly you would notice a failure and how quickly it could be fixed.
Why does trough flow rate matter and not just tank size?
Because stock drink in bursts, usually after milking or in the evening, and a trough that refills slowly runs dry exactly when the mob wants it. Sizing the pipe and pressure to the peak hourly draw rather than the daily total is what stops that. A large tank behind an undersized line still gives you thirsty animals.
Water Usage Cost Calculator NZ
How is a metered water bill worked out?
Where water is metered, you pay for the volume you use, measured in cubic metres, at your council's price per cubic metre, sometimes with a fixed charge on top. One cubic metre is 1,000 litres.
How much water does a household use?
Use varies widely, but a rough guide is around 150 to 200 litres per person per day, more with a garden, pool or long showers. This calculator lets you enter litres per day to estimate your bill.
How can I lower my water bill?
Shorter showers, fixing leaks, efficient appliances and careful garden watering all cut usage. Because a metered bill is directly tied to volume, reducing use translates straight into a lower bill.
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Every question the site answers
Answers are gathered from the calculators and guides listed above and are general information, not advice. Last reviewed 2026-09-06. See also the finance glossary, the guides and the reference data.