Yet another home heating question: options with heat-pump install

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ShinyChrome

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#273012 30-Jul-2020 16:23

It must be winter, eh?

So we are looking at heating options for the bedroom side of our house; predominantly heat-pump based, since that is what we use in the rest of the house. We are expecting, so are primarily concerned with heating a single bedroom; however, we had thought if we went for a large heat-pump in the hallway that connects all three bedrooms, we could essentially heat all 3 and the hallway to a stable comfortable temperature since we are likely to be running it for long periods of time during the day when home, or overnight. Then add in something like a dehumidifier to give the bedroom a small boost.

Our house is a typical 1920s-30s 3 bedroom, 140m2 bungalow; floor layout below (taken from the original builder's plans):

The bedroom in question is marked by the orange tick. We currently have an older 8.5kw unit in the lounge and a slightly newer unit in the main bedroom (not sure of the power rating, but I'm gonna say around 2.5kw), as marked by the green lightning (it's Paint 3D, ok?). There will be a door between the lounge and the hallway, so we can essentially close off each side of the house. We are also planning on getting thicker curtains and adding carpet in the bedrooms and we already have ceiling and underfloor insulation. I also know I need to do a bit of work stopping giraffes draughts around windows/doors.

We have gotten two quotes from two different installers so far: Installer A quoted us ~$3.5k to install a Daikin Cora 7.3kw unit in the hallway above the front door, as marked by the blue cloud; and Installer B quoted us for the same location as well (although theirs was ~$3.7k for a 4.6kw Daikin unit), but was heavily trying to steer us towards a 2.5kw unit in the middle bedroom (~$2.5k) or both rooms (~$4.7k), as marked by the purple clouds.

Aside from the obvious upsell, I understand heat-pumps generally work better as a room heat source than a general area, and that with one unit in the hallway, no matter how large, it will still take awhile to heat up the whole area and always be warmer in the hallway than the rooms. I'm wondering if jamming one in each room is a bit overkill for heating though, and well, the cost is really starting to get up there with two, but then again, only having one in the hallway might be a problem in a good few years, when closed doors will be a thing again.

So now we are unsure what is going to be the best option in the long run, especially since Installer A actually measured the area, whereas Installer B just used the old eyeball-o-meter. I'd started looking at other heating options, but really I like the safety, convenience, and efficiency of heat-pumps to be honest, even with the heavy up-front cost.

Thoughts?

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#2531501 30-Jul-2020 16:58

Generally heat pumps do quite poorly at heating rooms they are not in. A lot of kiwi's are used to fireplaces where the heat flows better.

(I do use my heat pump that way, but my house is built on the side of a hill & the heatpump is at the lowest point. Heat flows upwards a bit, but the rooms are much colder than the lounge)

If you are keeping your home warm most of the time, you should't need a dehumidifier.

If you have a roof-space with reasonable access, you could go for central heating for ultimate comfort ($7000 - $14000, you would likely be towards the lower end of the scale if ignored the rooms already with heat pumps in the sizing calc. (Although they are a little less efficient due to heat loss through the ducts.)

timmmay

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#2531529 30-Jul-2020 18:09

Ducted will be your best bet if you go with heat pumps, at about $12K. You don't actually need much power in bedrooms, we find 1000W oil heaters are off most of the time, in our old, well insulated house that we preheat with two heat pumps. Alternately wall mounted heaters with timers would work well as well, and take up less space and cost maybe $500. Run cost isn't huge, given you don't want heaps of heat in bedrooms.

Heat pumps do heat around corners, slowly, and it takes hours to take the chill off.

jonathan18

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#2531533 30-Jul-2020 18:24

First, congrats on the sprogging-to-be.

Second, enjoy your freedom, while you have it.

Third, learn from our mistake in thinking a large capacity heat pump in a shared space would heat the bedrooms off it. It didn’t.

Fourth, yep ducted systems are awesome (in theory and when well-designed and installed) but see the next point.

Fifth, happy to share my experience with some of the local installers; just PM me if interested...

Froglotion

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#2531746 30-Jul-2020 21:23

Hard call. It's a shame you already have heatpumps in other areas, a smaller ducted unit would heat / cool that place nicely. I'm not going to comment on the best way to solve your problem, as I don't know. But i'd consider pricing up a small (relative to other models) ducted unit. Could be to either do everywhere, or can just do bedrooms. I think one brand did one called a Sleep Pump or similar, was designed to cover bedroom heating requirements. Ducted isn't cheap however, but the advantage would be that you wouldn't need to run the other heatpumps, as it could cover all of the homes heating requirements from the roofspace.

Another option, as mentioned above is to install a wall heater, which can run on timer / thermostat. Shouldn't take much to heat the room, so that's something i'd look into too. They are pretty low profile and suited to that sort of thing. I tend to only see them in hallways when people install no heating at all in the bedroom area. But one installed in a small bedroom would sort the heating with ease.

elpenguino

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#2531755 30-Jul-2020 21:48

I also give my congratulations on your fully functioning reproductive system.

Re heating one bedroom:

To give you some idea of one option, we have one eco-heat type panel heater in a 3x5m bedroom. It's rated at about 400W. The bedroom has been totally insulated and also has a double glazed window with curtains.

The heater takes a few hours to get going when it's switched on in the evening but by bed time the room is toasty. I think if the insulation was patchy or the room was drafty, such a heater would struggle to heat the room. The heater was only ~$200 so it's a cheap experiment if you want to try one, or try an oil column type heater to see if how much energy you need to heat the room.

Most of the posters in this thread are just like chimpanzees on MDMA, full of feelings of bonhomie, joy, and optimism. Fred99 8/4/21

Handle9

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#2531787 31-Jul-2020 05:39

Congratulations. Enjoy time, toys and cash. You'll never have them again and you won't miss them :)

Will you definitely be in the house more than 5 years? If not use electric heaters and save the cash for essentials like OLED TVs and Atmos. If you are 100% certain you will be there for 5+ years (you probably won't be unless you have to be) then buy small cheap units for the kids rooms.

You will not recover the money it costs you to invest in heat pump under 5 years and for the first 2 years of your kids life $4k money in the bank is more security. After that you will know what your life looks like, and can plan accordingly.

timmmay

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#2531789 31-Jul-2020 07:15

Just noticed you said you were expecting, congratulations :)

We found when we had our baby the whole house needed to be warm all the time. We ended up having heat pumps at both ends of our house on 24/7, turned down at night. It cost us less than we expected given we've insulated the old house fairly well, and the house felt much warmer than when we turned the heating on and off. Heating through seems to be the key.

For bedrooms, I really just suggest mounting a heater on the wall and using a timer like the Kasa Wifi timer from PBTech. Panel heaters can usually warm the room enough, but won't cause horrible injuries if they're touched. Little kids learn not to touch things pretty quickly.

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mclean

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#2531890 31-Jul-2020 09:54

The cheapest way to do multiple rooms while keeping separate ON/OFF and temperature control in each room is to use a small multi-split, ie a hi-wall fan coil in each room, all connected to a single outdoor unit. You can run just one or two rooms if you want - when you do this the outdoor unit will be a bit oversized and will be even more efficient. Hitachi and Daikin have good small systems.

ShinyChrome

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#2531955 31-Jul-2020 10:57

Thanks for the comments guys, really appreciate the feedback and it's given me a lot to think about. It's an interesting time, and definitely learning a lot of things that I'd never had to consider previously!

While I agree a central ducted unit is the superior option, unfortunately our budget does not extend that high. Which is a shame, as with the age of our house we have plentiful access above and below (raised piles). We are also planning on moving to a bigger house after the first one, so I'm unsure of whether the investment would be worth it in the short-term. We are planning on taking advantage of the $5k interest free loan for home heating and insulation that our bank offers, so its not quite a big cash outlay upfront, but paid off over 4 years.

After going back-and-forth with the two quotes, I'd wondered if just saving the cash and getting some electric heaters would be a better option, but the potential safety issues and the general consensus that most of them were subpar for keeping a consistent temperature setting in an area (which could be just me getting the wrong end of the stick).

@Scott3: We had kind-of experienced this with our lounge heatpump, which does great at keeping the large area well-heated, but temp definitely drops as soon as you step into the hallway. Which funnily enough also has a fireplace, but I'm sick of the rigmarole of fireplaces haha. I'd hoped another big one heating the hallway would balance it out, but it sounds like that is not the case. I had made the comment about dehumidifiers since I had read that they do an alright job of adding a small amount of heat to the space, as well as the obvious dehumidifying element; was unsure how appropriate that was for a bedroom, though.

@jonathan18: PM'd!

@Froglotion: Yes, if we didn't have existing heatpumps, I would probably have just gone all-in on a central ducted solution. The consensus seems to be that something like an electric wall-heater might be the best option for individual bedrooms, and deal to the hallway separately. I'll have to look into what options are available with timers and thermostats.

@timmmay: Heating the whole house (or just the bedroom side at night) was pretty much what we were thinking, as it will make those 3am wake-up calls easy to deal with in winter! We had found even with the two heatpumps going, our bills were never outrageous, thus my first inclination to get another heatpump. And as you say, we will pretty much be running heating constantly for the 1st year at least. The wall-heater option sounds like the way to go for bedrooms though.

@elpenguino: I know, I was just as surprised as that it did the job after the many years of abuse, but there you go haha. We had had an eco-panel-heater in another house previously that never seemed to work and put me off entirely, but then again, that was a big ole' villa bedroom, so as you say, would struggle. Good point about the cheap experiment though.

@Handle9: Haha, I had been using that excuse to justify a few acquisitions lately! 5 years; Probably not, we were planning to look at a bigger/more rooms and newer house in a couple of years. Yeah, that had been playing on mind as well, even though we are getting an interest free loan to cover it. The fixed repayment cost is miniscule, but I see your point and I'd be more concerned about whether it would be dead money come resale time. I do like the point about saving money for an OLED though... and one of the reasons I want to move to a newer house is so we can have a room I can actually do atmos in haha

Again, thanks for the replies team.

All things considered, would it still be worth looking at a single heat-pump sized for just the hallway (roughly 15m2), and then electric heaters in the bedrooms where we need it? Or is there a better value way to heat a longer area like the hallway?

timmmay

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#2531958 31-Jul-2020 11:00

Unsure if another heat pump would help much. A heat pump in the area marked 14x12 could heat the hallway and put a bit of heat into the bedrooms. I still reckon wall mounted heaters in bedrooms are likely sufficient, but a heat pump somewhere central might keep the general house temp up and pre-heat bedrooms a bit.

ShinyChrome

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#2531961 31-Jul-2020 11:06

mclean:

The cheapest way to do multiple rooms while keeping separate ON/OFF and temperature control in each room is to use a small multi-split, ie a hi-wall fan coil in each room, all connected to a single outdoor unit. You can run just one or two rooms if you want - when you do this the outdoor unit will be a bit oversized and will be even more efficient. Hitachi and Daikin have good small systems.

Thanks, I'd only read up on those after getting the quotes, so I'm unsure if that was what the second installer proposed or two single-splits, but the multi-split makes more sense. As with the other replies though, and given the fact we will probably not be there for ever, the better value-for-money might be electric heaters in each bedroom, and something else in the hallway.

I must admit, both units we have are Fujitsu's and seem a little bit clunky, but both are over 7 years old now. I think if we do go with another heatpump, Daikin seems to be a top recommendation. I haven't heard a lot about Hitachi units, but will have a look around.

ShinyChrome

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#2531964 31-Jul-2020 11:13

timmmay:

Unsure if another heat pump would help much. A heat pump in the area marked 14x12 could heat the hallway and put a bit of heat into the bedrooms. I still reckon wall mounted heaters in bedrooms are likely sufficient, but a heat pump somewhere central might keep the general house temp up and pre-heat bedrooms a bit.

Sorry, I realised that layout is a little out-of-date (dated 1933 haha). The areas marked 14x12 and the 'Living room' or 17x14 are one space now with no wall in-between and are all heated by an existing 8.6kw unit.

Disregarding the bedrooms and bathroom, (3 rooms on the left side of the house), I'd be looking at the "hallway" as the T shaped area in the middle, and shut off the right part of the house by a door, marked in black. So roughly 15m2 in area.

neb

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#2532086 31-Jul-2020 13:21

ShinyChrome:
Our house is a typical 1920s-30s 3 bedroom, 140m2 bungalow; floor layout below (taken from the original builder's plans):

I'm missing the servant's quarters and coach house... do you still have the brass bathtub shown in the plans (I assume that's what's in the 7x6 room)? What's the 8x4 room before the laundry?/toilet?

ShinyChrome

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#2532138 31-Jul-2020 14:04

neb: I'm missing the servant's quarters and coach house... do you still have the brass bathtub shown in the plans (I assume that's what's in the 7x6 room)? What's the 8x4 room before the laundry?/toilet?

I'm guessing they left those behind on the original estate when it was moved onto site in the early 1990s haha.

Yes, the 7x6 room is the bathroom, but unfortunately not, they decided to renovate the bathroom in the late 90s-early 00s, so now we just have a small shower cube. The #instagrammable picture value would have been off the charts if it was still original...

I honestly don't know, but there was toilet in the laundry, so maybe it was like a pantry or additional storage? The wall between that room and the kitchen was removed, so now it is just part of the kitchen area. If the other half didn't want a big laundry for storage, I would knock it all out and create one big space.

Also, does anyone have any recommendations for wall-heaters?

timmmay

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#2532142 31-Jul-2020 14:16

I'd just go into M10 / Briscoes and look at the panel and convection heaters. I'd probably want one that can put out at least 1kw to help with warming the room, though once it's warm it usually doesn't take much power to keep a well insulated bedroom up to about 20 degrees. Consumer will have recommendations for individual models / brands.

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