Home Forums General Discussion Heating Assessment Tool Reply To: Heating Assessment Tool

Ian McChesney

Hi Adam
You raise an interesting point re the heating tool, and I have heard similar sentiments from elsewhere.

Last year, while the Healthy Homes Standards were still in draft stage I went through an exercise comparing the heating requirement of a hypothetical room using the draft methodology outlined in the HHS discussion document with a number of ‘methodologies’ that were used to size heaters by heat pump installers, some energy advisers (including CEA) and Consumer NZ. I used the same criteria for all e.g. the internal room temperature was 21C for all. At that stage the draft HHS heating calculator was resulting in a heater size typically 10-20% larger than the other methodologies. However, I haven’t gone through the final HHS methodology to see whether there have been changes, but neither have I verified the various ‘rule of thumb’ methodologies that have commonly been used by heat pump suppliers/advisers.

By and large I agree with Richard’s points but would comment on a few things:

1. I think extra capacity in heat pumps is generally a good thing, for the reasons Richard outlines, but I can see the issues caused when existing heat pump installations that up until now have heated the room satisfactorily are deemed too small under the HHS heating tool. It seems to me that the solution offered under the regulations – installing supplementary resistance heating up to 1.5kW – may not much of a solution at all and in some situations could be quite retrograde.

2. Regarding the information requirement to check heat pump outputs at the various external design points i.e. -4C for Christchurch, and variable throughout the country. This is not necessarily readily available information especially for existing heat pumps, and it boggles the mind that this information will need to be accessed in order to sign off compliance for each individual installation. I think there is a strong case to request Government post this information online for the main heat pumps sold in the last 10-15 years. I’m sure this would save a lot of time/duplication of effort from those checking compliance. Previously the EnergyWise site used to have a database of heatpump performance – can this not be re-purposed and expanded to meet the need here?

3. Indeed, as Richard says, the healthy homes regulations sets the legal requirement, so right now that’s it. I would note however that this particular regulation – the heating standard – is potentially at threat. The National Party last month promised, should they be the government at the next election, to repeal the heating standard of the Healthy Homes Regulations, including the requirement for a heater to be installed in living areas, and the requirement for a specified heating output. No doubt they have support for this view from some landlords. Personally I think this would be a hugely retrograde step, having advocated for years to get heating standards in place. Nevertheless, if there are genuine concerns about what the current standard specifies, it might be useful to air these (internally). Amendment of a regulation, sooner rather than later, is infinitely preferable to repeal.