Rental property heating calculator is now available online.

Forums › Home Workshop DIY › Rental property heating calculator is now available online.

Aredwood

3885 posts

Uber Geek
+1 received by user: 1757

Subscriber

# 251570 2-Jul-2019 02:13

Under the healthy homes regulations, all rental properties must have qualifying fixed heating in the main living area that can heat that area to at least 18deg on the coldest days of the year.

The government has made an online calculator to help landlords to figure out how much heating capacity is required.

https://www.tenancy.govt.nz/heating-tool/

I have just run the calculator on the lounge in my own house. And it said that I need 15.9KW of heating capacity. This is for a large room with no insulation and lots of windows. So I was expecting it to need approx 9KW or so.

I already have a 14KW heatpump to heat that lounge. Which so far seems to be able to do so. I had previously assumed that that heatpump was way oversized for that room. So I was not expecting the results to say that it would be undersized or at best, only barely complying. And in reality, I also need to compensate for the outside temperature (assumed to be 1deg for Auckland) in calculating the heatpump capacity. As the 14KW probably relates to an assumed outside temp of 7deg or so.

Although I haven't yet accurately measured the room and window sizes yet. So I will get some accurate measurements and re run the calculator, and see if my 14KW heatpump will actually comply. (as well as figure out the capacity of my heatpump at 1deg outside temp).

How does everyone else's lounges compare? Does anyone have sufficient heating to already comply? Especially rental properties that already comply. Does anyone have a lounge that is small enough, that a 2.4KW electric resistance heater is deemed suitable?

My house is owner occupied, so this is purely an academic exercise for me in relation to my house. I'm curious as to what % of GZ members have compliant heating in their houses. (assuming that all houses and not just rentals are required to comply). And whether the results of the heating calculator match with your personal experience of heating your lounge. - Calculator says you have insufficient heating, but you can still keep your lounge warm. Or the calculator says that you have enough heating, but you are still unable to keep your lounge warm enough.

Also guessing that GZ members would be more likely on average to have enough heating installed compared to the general population. So it would be interesting to see how many of us actually do have enough heating capacity installed. And in relation to rental properties, Will they all likely to have sufficient heating installed by the deadline? (July 2021 for new tenancies, July 2024 for existing tenancies and HNZ properties) Or will there be gross non compliance in 2 years time?

SirHumphreyAppleby

791 posts

Ultimate Geek
+1 received by user: 388

# 2268138 2-Jul-2019 07:21

One person supports this post

I think this is a ridiculous requirement. Having looked at wall heaters for our own home, I have come to the conclusion that they are next to useless and not worth the money. Many will struggle to heat to 18C in a reasonable time. One model we tried fell short of the target temperature by in excess of 10C despite having a higher rating than our old oil heater.

A cheap portable heater placed where it is needed is far more efficient. In our case, I purchased a temperature 'timer' and a cheap micathermic heater which I place ~1m from the wall. Less than $100 total, and that combination will heat much more than the living room.

tdgeek

16989 posts

Uber Geek
+1 received by user: 3380

Trusted

# 2268167 2-Jul-2019 07:59

Had to look for what was suitable. I assume fixed means hard wired? Those cheap convection heaters would comply, like this?

We had an old Evantair one worked great

http://www.briscoes.co.nz/electrical/heating/convector-heaters/goldair-convector-heater-1800w-gcv265-1077290

Heating Standard - Types of heating devices

In most cases, the fixed heating device required will be a larger device such as a heat-pump or wood burner. In some cases, such as small apartments, a smaller fixed electric heater will be sufficient. The minimum size of the small fixed heater that will be acceptable is 1.5 kilowatts.

Some heating devices are inefficient, unaffordable or unhealthy to run, such as unflued gas heaters, open fires and electric heaters (except heat pumps) with a heating capacity greater than 2.4 kilowatts. These particular heating devices will not be accepted in the heating standard, meaning that while they can still be used, they won’t meet the standard and the landlord will in most cases need to provide an alternative, acceptable fixed heating device.

nickb800

2240 posts

Uber Geek
+1 received by user: 447

Trusted

# 2268222 2-Jul-2019 08:36

This is really interesting - seems like they're setting quite a high bar.

I ran the numbers on our small 4x4m lounge in Wellington, which was recently renovated so has R2.4 internal walls, R2.8 external walls, and one big french door. Above code minimum floor and ceiling insulation. We keep it at 21 degrees 24/7, as our baby was born premature. Once we dealt to draughty windows, a 1.5kw wall mounted panel heater was sufficient maintain that temperature through winter. The tool says we need 2.6kW - which unless we use the 'topup' exemption, puts us into (small) heat pump territory.

The topup exemption is interesting - you can topup with fixed electric heaters provided the topup is 1.5kw or less, and the existing heating was installed prior to 1 July 2019. Given the difficulty in proving when heating was installed, I'd pick that the stingy landlord solution will be an array of fixed electric heaters like this https://www.mitre10.co.nz/shop/kent-micathermic-panel-heater-2000-watt-white/p/297052

When I can dig out some measurements, I'll run through the calculator with our old house in Christchurch, now a rental. It had good floor and ceiling insulation, but nothing in the walls as a 1960s era build. Currently has a mid-sized heatpump, but I'm picking that the calculator will require a massive heat pump

geoffwnz

649 posts

Ultimate Geek
+1 received by user: 209

# 2268225 2-Jul-2019 08:39

According to a quick and dirty calculation, I need 4.4kW of heating and have 5kW available. I may have overstated the wall insulation level as I just picked what I though was about right.

Given we've just been through a couple of days of temps down to their annual coldest, I'm more than happy with the heating I have.

As a thought, for another property I frequent that has a log burner, is there a way to calculate the heat output of those? It's at least 25 years old now.

MotorDrive Rallying

blackjack17

867 posts

Ultimate Geek
+1 received by user: 240

# 2268232 2-Jul-2019 08:49

We have a 1950s house in Auckland that has a living space of around 60m2 as the walls have all been opened up.

Has a 9.8m2 glass conservatory attached as well lots of big single glazed windows. All the walls, ceiling and floor are insulated.

It says we only need 6.8kw.

When we brought the house it only had a 5.8kw heat pump which was enough to warm the house but not enough to make it toasted. We installed a 15kw wood burner and now can easily get the house to around 23/24 degrees.

raytaylor

3363 posts

Uber Geek
+1 received by user: 716

Trusted

# 2268833 2-Jul-2019 21:12

I am surprised they let 100% efficient electric heaters qualify - they should have put a room size limit on them in my opinion.

The wording could have been better for encouraging heat pumps.

Our 4kw heat pump in the lounge does most of the heating/cooling year round - just for the last couple of weeks I have had to turn on an oil heater in the far bedroom where it has dropped to below 5 degrees overnight.

Ray Taylor
Taylor Broadband (rural hawkes bay)
www.ruralkiwi.com

There is no place like localhost
For my general guide to extending your wireless network Click Here

ben28

112 posts

Master Geek
+1 received by user: 39

# 2268946 3-Jul-2019 07:37

For just our 4 x 8 lounge in Auckland I got 4.6kw. Its a 1970's house, single pane large windows on 2 walls . but got insulation in the walls and ceiling.

Personally in the depths of winter I would not want to spend money heating this room without pulling the curtains. During the day its a balancing act , open enough to not need to use lights , but keep as much warmth in. Why waste $!

Have 6kw heat pump in installed, that heats the kitchen/dining also no problem

bfginger

991 posts

Ultimate Geek
+1 received by user: 46

# 2269606 3-Jul-2019 23:58

I'm curious as to what % of GZ members have compliant heating in their houses.

Anybody without a certified Passivehouse who doesn't have a small lounge will be directed to install a heat pump. According to the calculator I'd need a 5.2kw unit. In the real world it never drops below 18c in there (sun and thermal mass) with no heating.

A small radiant heater on low can cost less in directly heating the people in a room than heating the entire space. Many renters will never run the mandatory heat pumps but they'll be paying for them. Some may end up heating their lounges less because they'll be paying $2500 - $3200 in higher rent for a heat pump which otherwise would have gone into heating. Then there's the $ they'll be paying every year for the HP's standby drain. The reason persistent passive ventilation systems are so popular with landlords is because many tenants won't turn on any extraction fans because they're paranoid of the electricity cost. Those people are not going to run a big heating machine any time soon.

I don't think it's a smart law. A better option would be mandatory insulation in the living area walls. It can be easily retrofitted and that would cut down on energy use instead of increasing it. And good insulation lasts the lifetime of the house instead of needing to be replaced after 15 years. The increased electricity use piles straight on the winter usage peaks which will drive up electricity prices as it will require greater generation capacity.

Has a 9.8m2 glass conservatory attached as well lots of big single glazed windows.

If you get a good low e window film installed on them it'd almost halve heat loss through the glass.