Sizing up the right heating for your home

Published 29 August 2018

Choosing the right heating for your home can be complicated, but it doesn’t need to be.

New Zealand homes are notoriously under-equipped for the winter, and a lot of people struggle to keep their energy costs down over the colder months.

This is generally made up of a few factors such as poor insulation and damp conditions, but inadequate heating is a big part of this too. To the point then, "are my heat sources sufficient?"

Heat pumps are now a popular addition to most homes, given that they deliver heat into the home generally at 3:1 above the kW drawn off the grid, i.e., for every 1kW of energy drawn they give out 3 KW’s of heat, but if they aren't sized correctly you may find that they underperform, or become costly to run. To size an area for a heat pump:

• First take the m² floor area, e.g, (5m x7m lounge) then multiply by ceiling height (standard homes are 2.4m).

• The next thing to calculate is the amount of kW's required given the expected performance of the home. For a home that is insulated above and below, walls and double glazed, use a factor of 50. Increase this by 5 for anything that may be lacking in the home (no insulation or double glazing requires a factor of 65.) For this example, the heating required for 84m³ area in a well-insulated home is 4.2kW, whereas a home lacking these measures will require 5.5kW for the same area. Then choose a heat pump that is a bit higher than your calculation so that it’s not overworked. In the above example, a 4.5 - 5kW heat pump is recommended.

When sizing for a bedroom (where heat pumps are generally too large) using our radiant heaters, measure only the floor area, then multiply the m² by 0.8. Example being a 20 m² bedroom x 0.8 would require 1.6kW. Otherwise, use the heat pump sizing method if using a convection heater. If you aren't sure about getting it right then book a free heating assessment with us and we can give you all the options. Hope this helps, stay warm this winter!