Clean home heating methods

Heat Pumps

A heat pump works on the same principle as a refrigerator, but in reverse. The heat pump takes heat from outside and puts it into the room. A heat pump gives between two and three times the heat value of its consumption of electricity. The most common type is a split system type, where the evaporator is mounted outside the house wall, and a condenser is mounted inside on the floor, or wall. Heat pumps provide a dry heat, so there will be no condensation or dampness problems. Heat pumps can also be used for cooling and ventilation in summer. There are many different types available including floor standing and wall mounted heaters.

Inverter Models

An inverter heat pump detects subtle fluctuations in room temperatures and adjusts automatically unlike a conventional type which starts and stops repetitively. An inverter heat pump heats up more quickly as well and has an improved heating performance at low outside temperatures. An inverter heat pump is 30% more energy efficient than a conventional type, but generally costs more to buy.


Most heat pumps have refrigerants that have an ozone depleting potential (ODP), although this potential is significantly lower than the older hydrochloroflorocarbon (HCFC) type of refrigerants. It is possible to specify a zero ODP refrigerant, but this typically adds several hundred dollars to the price of the heat pump.


Heat pumps are highly controllable, allowing you to choose the temperature of the room and when you would like the heat during the day. Many heat pumps have additional programmable features. Heat pumps operate quietly and some have an additional 'sleep' mode feature that allow very quiet operation.

Running Costs

Since heat pumps are two to three times more efficient to run than radiant or convection electric heaters, their running costs are typically two to three times lower.

Flued Gas LPG Heaters

There is a big difference between a flued gas heater and a mobile or portable gas heater. Mobile gas heaters are commonly used in Nelson, but when used they produce a lot of moisture and sometimes gas smells inside the room. On the other hand, flued gas heaters produce a dry, smell free heat in the room as all the combustion products (water and gases) go out of the flue.

It is possible to buy flame-effect fires, both free-standing and in-built models are available, but the most efficient are Energy Saver gas heaters with efficiencies of 85%.

For flued gas heaters, it is usual to have two 45kg gas cylinders installed outside the house. These are hired from the gas company who regularly come to fill them with gas.


An advantage of gas heating is that it can be highly controllable with the options to have both a temperature thermostat and a programmable timer. The thermostat senses the temperature of the room and switches off the heater once a pre-set room temperature has been reached, and the timer allows you to choose the times of the day when you want heating.

Pellet Burners

Pellet burners are a new type of home heating in New Zealand and are favoured by clean air planners because they are relatively 'operator proof'. You buy pellets (that look like the rabbit variety) made of sawdust - meaning there's no burning of wet wood, and as the fire turns itself on in the morning there is no smoky overnight bank up.

Though its cost — around $3,300 plus installation — puts it at the top end of the woodburner price list, at under $5 a day to heat the whole house the operating cost is about the same as older woodburners and it is a lot more effective, with an even heat output all day.

The big benefit is the convenience. The fuel is fed in automatically - you only have to add pellets ot the hopper every couple of days. The fire is set to come on automatically (air heated by an electric glow-plug ignites the pellets). The emission rate with the highly efficient combustion of pellets is very low, and it doesn't need a big chimney. It produces very little ash and goes for around two days (burning for up to 15 hours a day) on one bag of pellets. The downside of pellet burners, for some, is that they need electricity to operate. But battery backup can generally be installed.

Council's approved list of ultra low emission pellet burners.

Diesel Heaters

Again these are flued heaters so that the combustion products are extracted from the room. A diesel tank would need to be installed near the house, which can be costly, but again this would be filled on a regular basis by the supply company.

These heaters are highly controllable with options to have both a temperature thermostat and a programmable timer.

Low Emission Wood Burners

If you plan to install a replacement wood burner, it must be an approved Council 'Clean Heat' type, i.e. it must have a heating efficiency of at least 65%, and an emission rating below 1.5g of total suspended particulate per kilogram of fuel burned. Select the correct burner size for the area you want to heat.

The label to the right on appliances gives the Council authorisation number for that model. This shows that it is a Council approved appliance. Check that this number is the same as the one on the Council Approved Burner List.

Council's authorised burner list.

The wood burners on this list have a range of emission ratings from 0.3g/kg up to 1.5g/kg. You can minimise Nelson's pollution by choosing a woodburner with the lowest emission ratings, by using seasoned wood, and by using the woodburner correctly.

You must check that your existing fire or burner is lawfully approved by the Council. If it was not 'lawfully installed' ask at Council about getting an inspection to authenticate the burner. This helps the process of installing a new one. You must also obtain building consent to install your new solid fuel burner. To find out about burner authentication, building consents, or to lodge an application, visit Council offices.

The Council has established the Good Wood scheme with firewood suppliers who guarantee to only sell wood that will comply with the Council's winter burning requirements.

Read more about Council's Good Wood scheme.