Location Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Average
Kaitaia 6.0 5.4 4.6 3.2 2.4 1.9 2.1 2.8 3.8 4.7 5.5 6.1 4.1
Auckland 6.4 5.6 4.7 3.3 2.3 1.8 2.2 2.8 3.8 4.9 5.8 6.4 4.2
Hamilton 6.0 5.3 4.6 3.1 2.1 1.7 1.9 2.5 3.5 4.4 5.5 6.1 3.9
Wellington 6.6 5.5 4.5 2.9 1.8 1.4 1.6 2.3 3.4 4.7 5.8 6.3 3.9
Nelson 6.5 5.7 4.2 3.1 2.1 1.6 1.7 2.4 3.7 4.8 5.8 6.4 4.0
Christchurch 6.1 5.2 6.0 2.6 1.7 1.3 1.4 2.1 3.4 4.7 5.7 6.2 3.7
Dunedin 5.1 4.8 3.3 2.3 1.4 1.0 1.3 1.9 3.1 4.0 4.8 5.3 3.2
Queenstown 6.6 5.8 4.3 2.8 1.8 1.3 1.6 2.4 3.6 5.0 6.0 6.8 4.0
Invercargill 5.7 4.9 3.3 2.2 1.3 1.0 1.2 1.9 3.1 4.3 5.5 6.0 3.4
Chatham Islands 5.6 4.7 4.2 2.4 1.5 1.1 1.3 2.0 3.0 4.2 5.3 5.8 3.4
Scott Base 7.1 3.8 2.5 1.3 1.1 0.0 0.0 0.0 0.7 3.1 6.5 8.1 2.6
The Boilerhouse Specialists in central heating systems.

Looking at home heating, considering central heating? You've come to the right place. We will guide you through the choices you need to make to decide which central heating system is right for you.

Get a free quote

Build your own central heating system

A 3 step process: use our calculator to determine your heating needs, then select the components of your customised central heating system.

Step One: Design your system

There are several variables in determining how much energy each room needs. Here you can enter the details for each space & build up a total home system.

Add Room
Hours a Day Days a Week Months a Year Annual Running Cost$
Winter Power Price$ per kWh Annual Running Cost (electricity)$

Step Two: How much will it cost?

Central heating can be a significant investment and we’d like you to be sure this is realistic for you. There’s quite a few factors in pricing a system but you do need to know what sort of cost is involved in central heating. From your heat loss calculations and system selections we’ve got a pretty good idea of the initial and on-going running costs you’re looking at for a central heating system. Most importantly, alter the fuel to see the impact on running cost.

Total Cost
Annual Running Cost

Step Three: Upload your details

Now that you’ve seen what is possible, refined your homes’ heating and decided that central heating is for you; here’s the next steps. We invite you to send your choices, plans and contact details to us. We’ll be in touch soon to discuss your best way to get the warm home you deserve.

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Thank you for taking the time to send us your information, we will get in touch with you shortly.

Boilers & Fuel

Choosing a boiler

Heating radiators or underfloor requires a heat source and here there’s plenty of options. This heat usually involves burning something.

Options are: Diesel boiler, Gas boiler, Solid fuel boiler, Wood boiler, Coal boiler, Pellet boiler. Where to start?

Fuel sources

Here’s an important choice, the fuel will dictate the on-going running costs of the system and how much work there is for you.

The chosen fuel for the boiler depends on you and your preferences.

Benefits, potential problems and running costs:

We’ll compare these with electricity, as we’re all familiar with this.

(Keep in mind that, as a general rule, the cheaper the fuel, the more work involved.)



Cost to run

Easy to use – no handling required, safe and convenient.
Most electric heating appliances are 100% efficient.
The bill.
Moderate carbon foot-print with gas and coal fired generation.
Take a look at your power account and the unit rate.  Ranges from 17 to 26 cents per kWh are normal.
Clean burning in modern wood fires.
Low cost.
Depending on your wood source it may keep you fit.
Near zero carbon foot print.
Wood needs to be cut, seasoned and stacked. The boiler needs manual filling, ash needs removing and the heat exchanger needs cleaning 4-5 times per season.
Not as controllable as more automatic solid fuel boilers.
Good seasoned soft wood has about 1,650kWh of energy per cubic meter or, around 1,300kWh after the boiler efficiency is allowed for.
Divide the cost of your wood (per m) by 13 for the cost in cents per kWh.
So if you’re paying $65 a cube, that’s 5 cents/kW.
Wood pellets are consistent, easily handled and allow automatic operation of the burner.
Wood pellet burner emissions exceed the Ministry of Health standards.
Near zero carbon foot print.
Pellets must be brought to the burner as delivery options are not flexible.
Pellets (in 15kg bags or your own containers need stacking then placing in the boiler.
Ash must be removed (about 1% of the fuel).
The heat exchanger must be cleaned 2-3 times a heating season.
One tone of pellets provides 5,100 kWh of heating after the boiler efficiency is allowed for.  Find out the cost of a tonne of pellets near you and divide this by 51 to get the cost in cents per kWh.
Pellet prices vary around the country, typically ranging from $500 to $650 per tonne, i.e. 9.8-12.7 cents/kW.
Gas (LPG)
Low initial cost, gas boilers are inexpensive.
Easy to organise – bottles can be delivered.
Annual service only needed on the burner- by qualified person.
High CO2 emissions.
LPG will yield 12.5kWh per kg in a conventional boiler or more in a condensing boiler but the cost is still over 20c/kWh.
Natural Gas
Low initial cost, gas boilers are inexpensive.
Easy if there is gas to your property.
Annual service only needed on the burner- by qualified person.
Not available in the South Island and rural North Island.
High CO2 emissions.
Connection fees apply whether you use little or a lot.
Consult your energy account or supplier.
Low cost.
Automatic boiler operation.
Modern coal boilers meet current Ministry of Health guidelines except in clean air zones.
Coal is dirty and dusty.
Needs to be delivered, stored, usually in bulk (1+ tonnes).
Up to 6% ash residue.
The burner needs daily attention.
Boiler heat exchanger needs cleaning 6-10 times a heating season.
High CO2 emissions.
Coal output varies between mines, you may expect 4,900kWh per tonne into your heated space.  Divide the delivered cost per tonne by 49 to get cost in cents per kWh.
Coal prices vary from mine to mine and with transport, the range is from $75 to $400 per tonne, i.e. 1.5-8.5 cents/kW.
Fully automatic when in operation. Boiler needs annual servicing only. Servicing by qualified persons only.
High CO2 emissions.
Divide the price per litre at the petrol station, by 0.105 for the cost per kWh (cents)
At $1,55 per litre is 14.7 c/kW.
Used oil (waste oil)
Fully automatic in operation.  Low running cost. Dirty.  
Fuel must be collected and stored.
Servicing by qualified persons only.
Maintenance costs can be high as contaminated fuel may damage the burner.
Forbidden by some local authorities.
Close to free but annual maintenance costs can be high.

Now; if you’re still interested in central heating you need to choose a fuel. If you want to fire your system with wood pellets, wood chips or cord wood we’re here to help. If you want something else we suggest you have a look at these:

Coal: www.mckenzieheating.co.nz

Diesel: www.waterware.co.nz

Gas: www.heatiq.co.nz

We’re all used to it and it is so easy, but that monthly account keeps climbing!
So, how long does it take to double the price if electricity increases at 7-8% a year? 9 to 10 years!
What if your fuel only rose with inflation at 3%? You’ll be paying twice as much in just under 25 years.

Other uses for heat
Radiators and underfloor in-slab pipes are not the only ways to use the heat generated by your boiler.
Your heat source can also be used for:
* Towel rails – can be heated by central heating and have an electric element for when the heating is not on.
* Hot water – the same energy that warms your home can heat all your hot water.
* Fan convectors – these are fan assisted heaters, great for an area with high heat load but not a lot of wall space.
* Spa or pool – easy to heat using a heat exchanger.