Home, heating & renovation

Topic

 

Home energy costs

Home energy costs

Keeping your home warm and showers hot in winter isn’t cheap. Around one-third of the energy supplied to our homes is used for space heating, with another third going towards hot water. So it makes sense to reduce your heating bill if you can.
We’ve calculated the rates charged for different ways of space and water heating based on the latest fuel cost data.

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.

Space heating costs

Electric space heaters run the gamut from efficient heat pumps to power-guzzling portable plug-in electric heaters.

Green Renewable
Orange Semi-renewable
Red Non-renewable

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.

Water heating costs

Natural gas (both instant and storage) is the cheapest way of keeping your shower hot, followed by heat pump water heaters and wetback woodburners. Most expensive are electric storage cylinders and LPG heaters.

Green Renewable
Orange Semi-renewable
Red Non-renewable

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.

Electricity

We looked into regional electricity prices and found the difference between the cheapest and most expensive retailers for a medium-sized household (in terms of annual bills on a 24-hour flat tariff) exceeded $1000 in the following areas; Northland, Waikato, Tauranga, Hawke’s Bay and Whanganui.

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]
Northland 1.20 0.32 1204
Auckland North/West 2.20 0.22 705
Auckland Central & Manukau 2.10 0.22 618
Waikato 2.41 0.27 1620
Tauranga 1.73 0.28 1268
Hawkes Bay 2.28 0.26 1231
Taranaki (New Plymouth) 1.06 0.29 881
Whanganui 1.07 0.29 1085
Manawatu 1.06 0.29 881
Wellington 2.31 0.20 698
Nelson 2.34 0.24 1081
Christchurch 0.94 0.28 1110
Dunedin 1.12 0.23 955
Invercargill 2.18 0.23 664

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.

Natural gas

Piped natural gas, only available in the North Island, remains the second-cheapest way to warm your home, costing 11¢ per kWh of heat on average.

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)
Whangarei 1.355 0.099 1.33% 0.68%
Auckland central 1.235 0.089 0.95% -0.66%
Hamilton 1.250 0.091 6.43% 8.33%
Tauranga 1.349 0.102 2.42% 0.85%
Napier/Hastings 1.584 0.085 -1.37% 11.94%
Taranaki (New Plymouth) 1.527 0.069 1.75% 4.85%
Whanganui 1.438 0.087 8.05% -0.07%
Palmerston North 1.630 0.083 2.20% 3.47%
Wellington (Hutt Valley) 1.658 0.088 3.17% 5.85%
Wellington 1.675 0.092 2.13% 2.41%

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.

LPG

If you live in the South Island or out in the wops in the North Island, and you’re keen on gas for heating or cooking, then LPG is your only option.

45kg cylinders

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
Auckland Contact (Rockgas) 97.75 115.00 None
Auckland ElGas 101.00 128.80 None
Auckland Nova Energy 107.84 135.29 15%
Auckland OnGas 101.90 128.80 None
Wellington ElGas 103.00 118.45 None
Wellington Contact (Rockgas) 97.75 115.00 None
Wellington Nova Energy 114.39 135.29 15%
Wellington OnGas 101.90 128.80 None
Christchurch Contact (Rockgas) 100.05 97.75 None
Christchurch ElGas 99.99 92.00 None
Christchurch Nova Energy 104.28 94.12 15%
Christchurch OnGas 106.90 98.12 None

9kg bottles

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 Bunnings 34.20
Auckland BP Fanshawe st 39.00
Auckland Z Ponsonby 35.90
Auckland Caltex Newmarket 39.00
Auckland Gull Kingsland 39.90
Wellington Bunnings Naenae 34.20
Wellington Mitre 10 Mega 35.00
Wellington BPAdelaide Rd 38.99
Wellington Mobil Johnsonville 37.49
Wellington Z Taranaki Street 39.90
Christchurch Mitre 10 Mega 35.00
Christchurch Bunnings 34.20
Christchurch BP Papanui 37.80
Christchurch Z Riccarton 37.49
Christchurch Caltex Hornby 35.90
Christchurch Mobil Papanui 39.50

GUIDE TO THE TABLES Prices are based on an April 2017 survey.

Firewood

The median price of a thrown (rather than neatly stacked) cubic metre of pine rose to $86 from $80 in 2016.

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 Comer Firewood 110.00 1 110.00
Auckland Ignition Firewood 270.00 3 90.00
Auckland Green Earths Firewood 70.00 1 70.00
Auckland City 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
Hamilton Captain Compost 120.00 1 120.00
Waikato Handy Stack 230.00 1.8 127.78
Rotorua Blazing Firewood 85.00 1 85.00
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
Fielding Fuge Firewood 420.00 4 105.00
Palmerston North Landscape Supply Yard 80.00 1 80.00
Palmerston North Tiritea Sawmilling Co. 80.00 1 80.00
Fielding Fielding Firewood 75.00 1 75.00
Napier Meeanee Firewood* 280.00 3.6 77.78
Hastings HBFP LTD 270.00 3.6 75.00
Hawera Hawera Firewood 200.00 3 66.67
New Plymouth Woodwards 230.00 3.5 65.71
Taupo The Wood Shed 95.00 1 95.00
Ohakune Deadman Firewood 90.00 1 90.00
Wellington Wellington Firewood 425.00 3.6 118.06
Wellington Ablaze 346.00 3.6 96.11
Wellington The Good Shed 390.00 3 130.00
Wellington Firewood Supplies 420.00 4 105.00
Wellington Firewood Unlimited 380.00 3 126.67
Wellington Woodyswood 310.00 3 103.33
Wellington SJ Firewood 120.00 1 120.00
Wellington Ezyburn* 395.00 3.6 109.72
Wellington Firewood Direct 585.00 4 146.25
Wellington Coastal Landscape (Waikanae) 270.00 3 90.00
Wellington Action Recyclers 340.00 3.6 94.44
Wellington Kapiti Firewood 280.00 3.6 77.78
Wellington Rubys Firewood 310.00 3.6 86.11
Wellington Firewood Plus 325.00 3.6 90.28
Wellington Composting NZ LTD* 90.00 1 90.00
Wellington Shauns Firewood 225.00 3 75.00
Christchurch City Firewood 265.00 3 88.33
Christchurch Davies Firewood 215.00 3 71.67
Christchurch Styx Firewood 250.00 3 83.33
Christchurch Garden Makers 80.00 1 80.00
Christchurch Christchurch Dry Firewood 200.00 3 66.67
Christchurch Gardening Supplies 75.00 1 75.00
Christchurch Ashley’s Firewood 220.00 3 73.33
Christchurch Top Cut 266.00 3 88.67
Christchurch Park House Garden Supplies 234.00 3 78.00
Geraldine Clearwater Firewood 195.00 3 65.00
Invercargill Parklands 75.00 1 75.00
Dunedin Dunedin Firewood 85.00 1 85.00
Dunedin Taieritree (Trade Me store) 240.00 2.8 85.71
Dunedin The Woodshed* 80.00 1 80.00
Dunedin Greenscene Firewood 320.00 6 53.33
Dunedin Foote Haulage 90.00 1 90.00
Dunedin Quality Firewood 98.00 1 98.00
Dunedin KB McKea Contracting 85.00 1 85.00
Ranfurly Wandsworth 517.50 6 86.25
Queenstown Highlander Firewood 300.00 3 100.00

GUIDE TO THE TABLE PRICES are based on an April 2017 survey. *Delivery fees apply.

Wood pellets

Wood pellets are made from waste wood shavings. They fuel specially designed pellet burners, which take the form of either single room fixed heating appliances similar to woodburners, or large central boilers that supply piped hot water and can power radiators for central heating.

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 20kgPrice for 15kgComments
Nationwidebroadys.co.nz (Natures Flame Brand)-$15.00-
NationwideMitre10 (Natures Flame Brand)-$11.88Only available in certain stores
TaupoNatures Flame Direct-$10.34NF 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-
WellingtonAblaze (Firetime Brand) $18.50--
WellingtonAblaze (On Fire Brand) -$14.00-
WellingtonBunnings (Firetime Brand)$12.25-Only available in certain stores
NelsonAzwood (Firetime Brand)$12.40--
ChristchurchPearsons Ltd Garden Supplies (Firetime Brand)$12.00--
ChristchurchPearsons Ltd Garden Supplies (Natures Flame Brand)-$10.25Currently out of stock
Christchurcheenergy.co.nz (Firetime Brand) $12.50--
Christchurcheenergy.co.nz (Natures Flame Brand) -$10.00-
Christchurchpottingmix.co.nz (Firetime Brand) $13.00--
Dunedinopf.co.nz (Natures Flame Brand)-$9.00 Note : $12.50 delivery fee
Dunedinopf.co.nz (OnFire Brand)$12.90- Note : $12.50 delivery fee
Central Otago mclellans.co.nz (Natures Flame Brand ) -$12.00-
InvercargillParklands (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.

×