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Home, heating & renovation
The results will be music to your ears if you’re blasting a heat pump this winter. In the past year, we found per-unit electricity prices rose by less than the rate of inflation. This makes heat pumps generally the cheapest way to keep warm.
That won’t be much consolation for those relying on their portable electric or LPG heaters, still the most expensive sources of warmth, costing more than 3 times as much to run as heat pumps. To make matters worse, fixed daily charges continue to rise, jumping 2.4% on 2016 and reflecting the increasing share of our bills taken by electricity distribution (lines companies) and transmission. But unless you’re going completely off grid, you’ll always incur fixed electricity connection fees, so they shouldn’t factor in your choice of heating appliance.
We’ve dived into heating costs and discovered eye-watering price differences between electricity and gas retailers. Our main finding? Shop around. The difference between annual electricity bills from the cheapest and most expensive providers can exceed $1000 in many regions (the gap is almost as much for gas), while a cubic metre of firewood can vary in price by more than $50 within the same city.
GUIDE TO THE FIGURES COSTS are for providing one kilowatt of heat for one hour. Bars represent range between maximum and minimum costs, black dotted line represents the national median. Electricity and natural gas costs are from powerswitch.org.nz based on April 2017 data. Other costs are from pricing data collected during April 2017. GST is included.
Heat pumps use electricity to shift ambient heat from the air outdoors into your home, and can transform each unit (kW) of electricity into 3 or more units of warmth. Despite electricity costing 26¢/kWh on average, a heat pump produces a kW of heat for 8.5¢.
In contrast, plug-in electric heaters convert electricity directly into warmth via a resistive element with a 1:1 efficiency, meaning each unit of heat costs 26¢/kWh.
The improved efficiency of heat pumps comes with a hefty price tag. They cost at least 10 times more than plug-in electric heaters to buy and install, and can’t be moved from room to room. So, despite their high running costs, electric heaters are often the most cost-effective option for small or occasionally used rooms, such as the office or bedrooms.
However, in decent-sized living areas a heat pump will more than pay for itself, while electric heaters (with a maximum heat output of 2400W) just don’t have the power to tackle anything beyond very small living areas.
GUIDE TO THE FIGURES COSTS (cents) are for providing enough water for a 10-minute shower.
Unfortunately, reducing your water heating bill isn’t as simple as ripping out your electric cylinder and installing an instant gas heater. Last year, a study by Concept Consulting found if your existing water heater is still going strong, the cost of buying and installing a new water heater will usually outweigh any savings in running costs.
However, many people switch for reasons other than economics, such as the endless hot water of an instant “infinity” gas system, or the environmental appeal of solar hot water. So, if your ancient electric cylinder springs a leak and reaches the end of its useful life, we recommend looking at your options. Despite its high running costs, LPG is worth considering if natural gas isn’t available, as it can have a relatively low installation cost.
|Location[sort; desc]||Average daily fee ($)[sort; asc]||Average 24 Hour/All inclusive fee ($)[sort; asc]||Difference between cheapest and most expensive retailers anually ($)[sort; asc]|
|Auckland Central & Manukau||2.10||0.22||618|
|Taranaki (New Plymouth)||1.06||0.29||881|
Note: towards the end of May, low rainfall in the South Island, coupled with colder temperatures further north saw spot (wholesale) electricity prices rise significantly. Greg Sise, Energy Link managing director, says that although South Island hydro lake levels are much lower than average for this time of the year, we’re still a long way from the sort of conditions that saw official electricity conservation plans in 2003. However, he urges consumers on electricity plans exposed to the spot market, such as the tariff offered by Flick Electric, to keep a close eye on prices so they can reduce consumption if there’s a spike.
Depending on where you live there can be big differences in the amount you pay in daily connection fees. Charges are lowest at the top of the North Island at an average of about $1.20 in Auckland and Hamilton and $1.35 in Whangarei and Tauranga. That rises to about $1.50 in Taranaki, Hawke’s Bay and Whanganui, while charges are highest in the Manawatu and Wellington, exceeding $1.80 for some retailers in the capital.
Unlike electricity, gas is a discretionary fuel, as you can often substitute gas-powered cooking or heating appliances for those powered by electricity. So if you’re paying that much in fixed charges and you’re worried about energy bills, consider either switching more appliances or your water heater to gas (once your old one fails), or ditching it entirely in favour of electricity. The upshot is it pays to maximize your use of the connection, especially if you live in the lower North Island where fixed charges are highest.
Since last year, there’s been a 3.8% rise in gas prices nationwide, reaching an average of 8.8¢/kWh. But the average per unit price falls to 7.6¢/kWh once you factor in prompt payment discounts.
|Location[sort; desc]||Average fixed rates ($)[sort; asc]||Average variable rates ($)[sort; asc]||Change from 2016 (fixed rates)||Change from 2016 (variable rates)|
|Taranaki (New Plymouth)||1.527||0.069||1.75%||4.85%|
|Wellington (Hutt Valley)||1.658||0.088||3.17%||5.85%|
GUIDE TO THE TABLE Prices are based on Powerswitch data from April 2017 and show the average fixed and daily gas charges excluding prompt payment discounts.
For 45kg cylinders you’ll pay an average annual rental of about $120 for 2 cylinders, along with a $100 cost for replacing each cylinder (the average household goes through 7 to 8 bottles each year).This makes LPG space heaters twice as expensive to run as natural gas heaters or heat pumps.
|Location[sort; desc]||Company[sort; desc]||Cost of 45kg cylinder ($)[sort; asc]||Cost of renting 2 cylinders ($)[sort; asc]||Prompt payment discounts|
We found prices for 9kg swappa bottles were fairly steady compared with previous years, with a median price of $37.49 nationwide for exchanging an empty cylinder for a new one.
|Location[sort; desc]||Supplier[sort; desc]||Cost of exchanging empty bottle for full bottle ($)[sort; asc]|
|Auckland||Mobile Mt Roskil||37.50|
|Auckland||Mitre 10 Mega||35.00|
|Auckland||BP Fanshawe st||39.00|
|Wellington||Mitre 10 Mega||35.00|
|Wellington||Z Taranaki Street||39.90|
|Christchurch||Mitre 10 Mega||35.00|
GUIDE TO THE TABLES Prices are based on an April 2017 survey.
But the difference between the cheapest and most expensive cubic metres is $71 in Wellington, and $55 in Auckland. You should call around to ensure you’re getting the best deal.
Not all firewood is created equal, with some suppliers seasoning their wood much better than others. You can check this by asking suppliers to show you moisture readings of their firewood. Based on the average price of $86, woodburners are almost twice as expensive to run as a heat pump. You can reduce running costs by making sure you’re burning dry firewood of the right size (less than 110mm in diameter), keeping the woodburner refueled, and burning cleanly by adjusting the amount of wood burning rather than turning down the air supply.
|Location[sort; desc]||Supplier[sort; desc]||Cost per load of pine ($)[sort;asc]||Load size (thrown cubic metres)[sort;asc]||Cost per one cubic metre ($)[sort;asc]|
|Auckland||Green Earths Firewood||70.00||1||70.00|
|Auckland||Chit Chat (Trade Me store)||275.00||5||55.00|
|Auckland||Manukau Firewood Yard||360.00||4||90.00|
|Tauranga||Bay Stump Removal||99.00||2||49.50|
|Gisborne||Bone Dry Firewood Supplies||120.00||1||120.00|
|Palmerston North||Andrews Firewood||290.00||3.6||80.56|
|Palmerston North||Palmerston North Firewood||240.00||3||80.00|
|Palmerston North||Landscape Supply Yard||80.00||1||80.00|
|Palmerston North||Tiritea Sawmilling Co.||80.00||1||80.00|
|Taupo||The Wood Shed||95.00||1||95.00|
|Wellington||The Good Shed||390.00||3||130.00|
|Wellington||Coastal Landscape (Waikanae)||270.00||3||90.00|
|Wellington||Composting NZ LTD*||90.00||1||90.00|
|Christchurch||Christchurch Dry Firewood||200.00||3||66.67|
|Christchurch||Park House Garden Supplies||234.00||3||78.00|
|Dunedin||Taieritree (Trade Me store)||240.00||2.8||85.71|
|Dunedin||KB McKea Contracting||85.00||1||85.00|
GUIDE TO THE TABLE PRICES are based on an April 2017 survey. *Delivery fees apply.
The median price of wood pellets increased 14% on last year to $13.67 per 20kg bag, bringing the running cost of wood pellet burners to the same level as logburners.
The 3 pellet brands are Firetime, Nature’s Flame and OnFire. Available at Bunnings, 20kg bags of Firetime pellets are generally the cheapest at $12.25 or less. You can save by buying in bulk and having them delivered. For example, Nature’s Flame reduces the cost per 20kg bag to $9.03 when you order 36 bags or more at one time.
|Location[sort; desc]||Supplier[sort; desc]||Price for 20kg||Price for 15kg||Comments|
|Nationwide||broadys.co.nz (Natures Flame Brand)||-||$15.00||-|
|Nationwide||Mitre10 (Natures Flame Brand)||-||$11.88||Only available in certain stores|
|Taupo||Natures Flame Direct||-||$10.34||NF prefer to deliver 36+ bags price reduces to $9.03. Collection may be discontinued from them directly, currently under review.|
|Upper Hutt||Fireworx (Natures Flame Brand)||-||$20.00||-|
|Wellington||Ablaze (Firetime Brand)||$18.50||-||-|
|Wellington||Ablaze (On Fire Brand)||-||$14.00||-|
|Wellington||Bunnings (Firetime Brand)||$12.25||-||Only available in certain stores|
|Nelson||Azwood (Firetime Brand)||$12.40||-||-|
|Christchurch||Pearsons Ltd Garden Supplies (Firetime Brand)||$12.00||-||-|
|Christchurch||Pearsons Ltd Garden Supplies (Natures Flame Brand)||-||$10.25||Currently out of stock|
|Christchurch||eenergy.co.nz (Firetime Brand)||$12.50||-||-|
|Christchurch||eenergy.co.nz (Natures Flame Brand)||-||$10.00||-|
|Christchurch||pottingmix.co.nz (Firetime Brand)||$13.00||-||-|
|Dunedin||opf.co.nz (Natures Flame Brand)||-||$9.00||Note : $12.50 delivery fee|
|Dunedin||opf.co.nz (OnFire Brand)||$12.90||-||Note : $12.50 delivery fee|
|Central Otago||mclellans.co.nz (Natures Flame Brand )||-||$12.00||-|
|Invercargill||Parklands (Natures Flame Brand)||-||$11.50||-|
GUIDE TO THE TABLE PRICES are based on an April 2017 survey and show the cost of a 15kg or 20kg bag of pellets, depending on what the supplier offers.
Find out how to keep heat in and dampness out, which fuels are the cheapest and cleanest, and how to get the most out of your appliances.
You’ll have a house so warm, you won’t want to leave until spring.
By George Block
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