Heating in typical NZ homes?

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#2715953 31-May-2021 09:20

decibel:

We built a new house about 8 years ago, double-glazing everywhere.

The BEST thing we did was a ducted heatpump in the roof. Very quiet but then, we don't leave it on overnight.

Curious what brand and what type of diffusers you have? Also where is the unit in the roof, above what part of your house?

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geoffwnz

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#2716591 1-Jun-2021 09:59

Daikin Ducted heatpump set to 19 degrees most of the time on the rooms that are in use with the occasional evening bumped up to 21 if guests are visiting.

Running it whenever the outside temperature is under 15 ish and not expected to get above that. If there's no other noise, I can just hear the air moving and sometimes the internal unit itself.

Having gone from one flued gas fireplace in the lounge and a timer set convection heater in the hallway outside the bedrooms, the house now maintains a comfortable 16-20 degrees most days and nights with the fan set to minimum. The one night the temperature dropped under 0 (Upper Hutt last week) the interior dropped down to 15 despite the unit set to 19. So I may have to set the fan to auto when I expect the temperature to drop that low. Still an improvement on a frozen face despite being in bed. :-)

House itself is insulated under floor, walls and ceiling. Single glazing though.

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Blurtie

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#2717319 2-Jun-2021 14:35

We're in CHCH and have a 1920s bungalow with insulation up top and about 3/4 of external walls and partial double glazing on the eastern and southern side of the house. No underfloor insulation or vapour barrier as house is too low to the ground.

For heating we run our main approx year old heat pump (at the entry/dining area) at 23C when we're at home, with two dehumidifiers running at each end of the house. I'm constantly amazed at the amount of water those things extract out. We have another older/ancient heat pump in our living area that we don't use as much as it's complete crap. Have thought about replacing it as it would make it more comfortable, but our current set up works pretty good so far.

We don't tend to heat bedrooms overnight. We renovated our two main bedrooms (on the eastern side of the house) last year and insulated the external walls and found that it did make a big difference in terms of heat retention. Will probably need to heat them once winter really sets in down here.

vexxxboy

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#2717333 2-Jun-2021 15:17

we live in a 1963 house for the past 23 years and we have ceiling insulation that was already installed. We live in Rotorua which has strict laws on wood fires so we replaced ours with a heatpump and it was the best thing we ever did. We were spending $600 a year on firewood to last the Winter and now with the heat pump it is down to $50-$60 a month over the winter period. We are now replacing the Batts with the best there are and putting insulation under the floor and it is costing us $475 with a government subsidy for the other 90%. I Will be interested if it makes any difference to the power bill. The govt is also interested as i had to give them permission to check our energy usage over winter as part of the deal.

Common sense is not as common as you think.

dipper

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#2717347 2-Jun-2021 15:39

We built a SIP's house (In Christchurch) two years ago with PVC Windows. We have a Nilan Ventilation System and a gas fire. The gas is also used for gas hobs. Looking at our sensors the house was 18.1 degrees this morning when it was -0.2 outside with only the ventilation system (that has a small heat pump in it) running. This is the coldest the house has been in the last month.

With the gas fire (and hobs) it takes us a year to use one 45kg gas bottle with the fire only used if we have had a couple of days without any sun shine or the in-laws staying as they complain about being cold unless hot air is blown onto them and the house ends up being closer to 26 degrees what it way too hot.

mattwnz

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#2717394 2-Jun-2021 18:27

Blurtie:

We're in CHCH and have a 1920s bungalow with insulation up top and about 3/4 of external walls and partial double glazing on the eastern and southern side of the house. No underfloor insulation or vapour barrier as house is too low to the ground.

I would worry about all that moisture coming up through the ground if you are getting lots of moisture collecting in dehumidifiers. Is the ground space well vented? Are you able to remove the floorboards in the future to install a vapour barrier and possibly insulation too? Or even excavate? Often when an old house like that gets repiled and is too low to get underneath it, it has to be jacked up. This is my concern with many of these older houses, they will need to be improved over time, and is one of the benefits of a new build. You notice the difference when you live in a new build compared to an old house. IMO we really nee to do more about retrofitting double glazing into these older houses, a the options in NZ aren't great and expensive.

Fred99

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#2717397 2-Jun-2021 18:48

mattwnz:

Blurtie:

We're in CHCH and have a 1920s bungalow with insulation up top and about 3/4 of external walls and partial double glazing on the eastern and southern side of the house. No underfloor insulation or vapour barrier as house is too low to the ground.

IMO we really nee to do more about retrofitting double glazing into these older houses, a the options in NZ aren't great and expensive.

I doubt that double-glazing would be effective in a typical 1920s house, usually with small windows.

You're only increasing R by only a little bit for a small window area, farting against thunder compared to possible low R value for external walls, ceilings, floors, but particularly poor sealing on door and window joinery. The latter might be the easiest to solve, but it depends. Often there's a lot of air flow between cladding cavities and joinery frames leaking around architraves etc - that's relatively easily sorted by sealing/refixing. If old joinery is stuffed, then it's a problem that perhaps replacement with new (and double-glazed) is the only sensible option. There are now approved systems for retrofitting external wall insulation without removing cladding or internal lining, there are probably a lot of things that need to be done that may give a far better benefit vs cost than retrofit double-glazing, which even on best case scenario isn't very cost effective. If replacing anything - or on a new build it's a no-brainer. But if curtains don't solve a heating issue, then double-glazing won't either.

Disclaimer: I like old houses with character. Whacking modern style double glazed joinery in a character house should have the owner put in stocks in the town square and pelted with decaying vegetable matter.

eonsim

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#2717426 2-Jun-2021 20:02

We are in a 1980's wooden house in Hamilton with reasonable insulation in all the external walls and some internal ones. Roof is concrete tile with some insulation and virtually no roof space. The tiles work pretty well as a massive heat sink on sunny days, and can keep the upstairs rooms in the 20's during the day (even with a 8C temperature difference between the outside temp) without heating. In summer the problem is keeping the rooms cool at night as the tiles hold the heat well into the night. And the upstairs will reach 2-4C above ambient temperature during the day which is more of a pain, and needs a lot of cooling.

For heating we have 3 heat pumps (1 multi-headed) 2 of which keep all the bedrooms warm in winter and cool in summer (roof tiles!). With one downstairs along with the Kent wood burner. At this time of year with out heating the house averages 18-22C during the day, and over night the downstairs (which isn't heated at that time) can drop as low as 15-16 when there is a frost outside, without a frost 17-18C is more common. With the fire going or heat pumps running it will tend to sit in the 20-22 range.

Will eventually get double-glazing as have some large windows, but it will be at least in part for the noise reduction and definitely reduced condensation (given the Waikato and all)!

decibel

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#2717442 2-Jun-2021 20:27

timmmay:

decibel:

We built a new house about 8 years ago, double-glazing everywhere.

The BEST thing we did was a ducted heatpump in the roof. Very quiet but then, we don't leave it on overnight.

Curious what brand and what type of diffusers you have? Also where is the unit in the roof, above what part of your house?

We have a Fujitsu unit (sorry, not sure of the model) in the ceiling above the laundry. All 4 outlets are circular, about 330mm in diameter - see photos.

timmmay

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#2717448 2-Jun-2021 20:45

eonsim:

Will eventually get double-glazing as have some large windows, but it will be at least in part for the noise reduction and definitely reduced condensation (given the Waikato and all)!

Double glazing may not be as good at noise reduction as you might expect. We had thick wooden single glazed windows with retrofit double glazing, they didn't let much noise through. When we went to PVC double glazing they actually let more noise in. The glass panel sits on spaces to allow water running down the window to drain, so all that's blocking noise for about 0.5cm on the sides is two thin pieces of PVC.

Double glazing helps a lot with condensation, but you need to ventilate. Ventilation systems are effective. You don't need to run them 24/7 as that makes things colder at night, we only run ours 4-5 hours during the day in winter.

timmmay

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#2717468 2-Jun-2021 21:20

decibel:

We have a Fujitsu unit (sorry, not sure of the model) in the ceiling above the laundry. All 4 outlets are circular, about 330mm in diameter - see photos.

That's interesting thanks @decibel. 330mm outlets are pretty huge compared with the 200mm standard most use, which is probably one reason it's pretty quiet. Do you have any issues with the heat staying up at the ceiling rather than heating up floor level? Those diffusers aren't always great at pushing air down unless you have a floor level return vent. We had a similar vent in 200mm and we found it was often 29 degrees near the ceiling and 22 degrees near the floor.

You have a huge ceiling space! Our is pretty big but not that big.

eonsim

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#2717471 2-Jun-2021 21:44

timmmay:

eonsim:

Will eventually get double-glazing as have some large windows, but it will be at least in part for the noise reduction and definitely reduced condensation (given the Waikato and all)!

Double glazing may not be as good at noise reduction as you might expect. We had thick wooden single glazed windows with retrofit double glazing, they didn't let much noise through. When we went to PVC double glazing they actually let more noise in. The glass panel sits on spaces to allow water running down the window to drain, so all that's blocking noise for about 0.5cm on the sides is two thin pieces of PVC.

Double glazing helps a lot with condensation, but you need to ventilate. Ventilation systems are effective. You don't need to run them 24/7 as that makes things colder at night, we only run ours 4-5 hours during the day in winter.

Right, my previous experience had been with double glazed windows in Europe where they did an excellent job of cutting down the noise. Most of the double glazing I've seen in NZ has not been of the quality that European stuff was though.

The roof design of the house doesn't really have any space for a ventilation system (inner cladding, building paper, insulation and tiles on top of the insulation), only place it might work would be at floor level on the upstairs leading into the crawl space, and that is effectively open to the external air as tiles are not anything close to air tight. Also the Waikato is pretty damp outside so...

JayADee

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#2717512 3-Jun-2021 07:48

1950 brick and concrete tile in Bay of Plenty. There are a tremendous amount of external wood and glass doors (5 including 3 sets of French doors) and large, single glazed, casement windows in this house which is letting in a lot of ‘ventilation' especially if we get a southerly. We have underfloor spun poly insulation and plastic on the ground in most places (one room is inaccessible from underneath), ceiling insulation (the lounge could likely use more, it was there when we moved in). Most walls were retrofitted with fibreglass but the spaces around the joinery weren’t insulated.

We have a high wall heat pump in the kitchen, a ceiling cassette heat pump in the lounge, a small high wall in the room where the floor isn’t insulated. It's a split system running from one outdoor unit. Mitsubishi. Installed around 2012. Works well in summer as air conditioning on super hot days. We have a wall mounted fan heater in the bathroom and an extraction fan over the shower that vents outdoors. An extractor fan in the kitchen that vents outdoors (and really needs replaced, was put in around 2003). We are in the process of replacing the original wood stove in the lounge so we have no wood stove until next summer.

We like sleeping cold so we don’t heat the bedrooms or corridors or bathroom either unless we're using it. We have an electric blanket to preheat the bed on really cold nights and generally sleep with the windows cracked open for moisture management and fresh air.

I've put as much draft stopping as I could around the doors and windows, added a draft stopper to the shower extraction fan and have curtains on the worst doors. I've got Venetian blinds on some of the windows like bathroom, kitchen where there is moisture or we need to moderate the light. The curtains make a difference.

I've been trying to think what to do when our lpg gas hot water heater and hob need replaced what with lpg on the way out.

Also what to do when the heat pumps need replaced.

We're both retired this year. A hot water heat pump is something I'm looking into, prefer an outdoor one as I don’t know where we'd put an indoor cylinder. I guess induction for the hob.

An underfloor ducted heat pump would be a possibility (lots of room under the floor and in the roof cavity) but the system we have now has worked pretty well for us and is already in place so should be a cheaper/easier replacement.

Any thoughts welcome for replacing what we have, especially on the hot water heater. Does anybody have an outdoor hot water heat pump cylinder?

Blurtie

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#2717520 3-Jun-2021 09:01

mattwnz:

Blurtie:

We're in CHCH and have a 1920s bungalow with insulation up top and about 3/4 of external walls and partial double glazing on the eastern and southern side of the house. No underfloor insulation or vapour barrier as house is too low to the ground.

I would worry about all that moisture coming up through the ground if you are getting lots of moisture collecting in dehumidifiers. Is the ground space well vented? Are you able to remove the floorboards in the future to install a vapour barrier and possibly insulation too? Or even excavate? Often when an old house like that gets repiled and is too low to get underneath it, it has to be jacked up. This is my concern with many of these older houses, they will need to be improved over time, and is one of the benefits of a new build. You notice the difference when you live in a new build compared to an old house. IMO we really nee to do more about retrofitting double glazing into these older houses, a the options in NZ aren't great and expensive.

When we renovated our bedrooms last year there was a random man-hole that I managed to get a look look at the subfloor, there's literally not much space down there at all. I did toy with the idea of excavating, but thought that it would take way too long so canned that idea.

We're in the process of getting our house scoped for missed earthquake damage (all signs point to yes so far) - so we may get the opportunity to lift the house, where we'll definitely look to insulate then. But until then, we're really in a holding pattern until we hear back.

Our set up works okay so far.. The past few cold frosty nights here in CHCH where it was near freezing point, the rooms in our house only cooled down to 15. Massive condensation on our single glazed windows/french doors - but recently bought a window vac to suck that stuff up!

mclean

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#2717808 3-Jun-2021 17:09

1970's house on Kapiti Coast. Concrete slab on grade with no insulation, 50mm f'glass in the walls & roof, single glazing in wood frames.

Heating is by a single clean-burning (NZS 2918) wood burner in the living area, which we run in the evenings during winter, and open the doors through to the bedrooms about an hour before going to bed. Plus manually controlled wall-mounted radiant heaters in the bathrooms for instant heat.

Our annual heating bill (for firewood) is around $360/year. For us, sitting around a heat pump in the evening doesn't quite cut it, compared to a flaming log fire.

McLean

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