Advice on home heating and/or ventilation

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Blurtie

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#249249 2-May-2019 13:56

Hi All,

After advice/opinions on what you would do in my situation.

Background: old house -3 bedroom, 1920s bungalow based in Christchurch, approx 100m2, partial double glazing (with cheap plastic inserts on some windows), good insulation in roof space, but nothing below due to low clearance and no access to under floor, 2 adults and a 3 yr old with the possibility of a new addition if/when it happens.

Presently just looking to heat the house during mornings/evenings. No one is home during the day, although that may/will change if we have a new arrival.

We've been in the house for almost a year now and I'm looking into options for heating the whole house rather than just single rooms. With winter approaching and noticeably colder mornings we do get condensation on the windows. We leave windows open during the day when we're out for ventilation.

There's currently two OLD (no name) heat pumps in the house - 1 in the lounge/tv area which is our main source of heating and we run a dehumidifier at the same time in the dining/kitchen area (semi-open space with lounge area - but lounge can be closed off). The bedrooms are in another part of the house and we use oil column heaters for heating.

We got a quote for a full ducted heat pump system when we first moved in which came in around $16k for a 14kw misti PEAD system (which I thought was a bit steep at the time). ; the guy mentioned that the 'good' thing with older houses is that they "breathe naturally and provide fresh air into your home" so a separate ventilation system wasn't necessarily required but could be added at a later time. Not sure if this is sound advice?

Our window frames are quite old, and I understand the typical cost to retrofit decent double glazing on our whole house would typically be in region of 10k mark. Although happy to be corrected from those in the know if this figure is way out.

But anyway, I am leaning towards a having a ducted system installed in the house. I see this as adding the most immediate impact rather than doing windows and/or further insulation, replacing our old heat pumps etc. Am i being delusional? Would ventilation/condensation still be an issue?

Haven't got my head on running costs for this system compared to what I'm doing now, but I understand that i can set it up to create different 'zones' and heat as needed? Would appreciate hearing from those that have this system and their experiences. I'm not overly concerned with getting a 'return' on this investment in terms of savings (if any) on my power bill, would much rather be comfortable in the house - unless you think it's going to be terribly inefficient and increase my power usage astronomically...

Just wanted to hear your thoughts/opinions and what you would do instead if say you had a budget of 10-15k in my situation.

TIA

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#2229472 2-May-2019 14:06

Others here will be able to advise you far better than me, but I had thought that the in-roof part of a ducted heat pump system can be very large and so not necessarily easy to put into an existing house?

EDIT: Do you have any insulation in the walls? It always seemed pointless to be to put double-glazing in if you have no wall insulation. It will reduce condensation on the windows, but will it really help much with heat loss?

EDIT 2: In an older house with single glazing I suspect that condensation will still be present in the colder months without a ventilation system as you aren't removing any moisture. Whether it is bad enough to be an "issue" only you could decide. And I've also heard differing arguments about how effective a ventilation system can be at removing moisture during winter if the outside air is equally as damp as the inside air.

jonathan18

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#2229486 2-May-2019 14:28

Yep, I would indeed recommend a ducted heat pump system - on the enormous proviso that it needs to be designed and installed by a company that knows what it's doing. I reckon there is far more in common between domestic and commercial ducted systems - which requires real thought and skill to do - than between the former and a back-to-back heat pump install.

Rather than list all that I learnt in the process of having our system installed, you could have a read through this thread (there are also heaps of others here on GZ which are worth reading): https://www.geekzone.co.nz/forums.asp?forumid=141&topicid=175823

I'm happy to be a cautionary tale of how not to get a system installed; late last year we paid another company to come and assess our install, and the verdict was not pretty - we're still working with the original installer to resolve the install problems, with them saying they don't know what's wrong. (The problem is the second opinion company doesn't want to tell us in detail what's wrong as they see it as 'helping the competition; to pay them to fix it was going to be like $2k, so we're in a bit of a bind!)

BTW, installing the inside unit in the roof space can be an issue; ours was able to be got through the hole they made for one of the returns, but I've heard in some cases they have to lift roofing to get it in.

Aredwood

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#2229505 2-May-2019 15:02

Get proper double glazing, with PVC window frames. As single glazing has a worse insulation value than even an uninsulated wall.

Which room has the second old heatpump installed in it?

Just get separate heatpumps installed in each room. The $16K that a ducted system would have cost, would easily pay for plenty of separate heatpumps. Smaller heatpumps have better efficiency. And by definition, excellent zoning.

Lots of houses have wildly varying heating and cooling loads between different rooms, and even different times of the same day. This is an absolute nightmare for ducted heatpump systems. Yet no problem for separate heatpumps In each room.

jonathan18

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#2229512 2-May-2019 15:15

It's clearly a matter of preference, but I really dislike retrofitted PVC and (especially) aluminium windows in a house where they so clearly don't match the age/design of the house. The worst is replacing wooden double-hung windows in an old villa with aluminium casement windows.

A 1920s house like the OP's, though, may well have casement windows (our house is of the same era and all ours are casement); I'm guessing the PVC windows can be made in similar styles to the original, rather than solely modern designs?

Also, I'm guessing that there are businesses in any large NZ city that will double-glaze existing wooden windows; my brother had this to some of his windows in his villa in Wellington. It's certainly not cheap, but it avoided the aesthetic desecration of the house.

wellygary

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#2229513 2-May-2019 15:15

First up, how much water are you pulling out the dehumifier on a daily basis?

If its a large amount then you first need to be looking at moisture sources, namely bathrooms, kitchen and possibly damp under floor dirt...

Needing to have open windows during the day is preventing you making much use of solar gain to help heat the house.

Then go hunting draughts, poorly fitting windows and doors + underfloor draughts etc,- you will always have some, but we double glazed a 1910s villa recently, but the biggest gain was from the sealing the windows we didn't use and the new draught seals on the ones we chose to have openable.....

Even if you don't double glaze improving the seals on windows/doors is probably a good bang for buck spend....

Then look at heating...

timmmay

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#2229519 2-May-2019 15:29

PVC double glazing in the $10k to $14K range, depends on window count and size. Ventilation system can help push out damp air during the day. Ducted heat pump is nice, but we do quite well with two large heat pumps and oil heaters in the bedroom overnight - the house is never cold. When we had a very young child we just never turned heating off, the bill wasn't so bad, only maybe 30% more than when we heated only morning and nice, but we were well insulated, double glazed, etc, even though it's an old house.

If I was starting fresh I'd consider an integrated heat pump / ventilation system, and expect to pay $20K. Next step down is two heat pumps and a cheap positive pressure system, on a timer so it only runs daytime in winter (9-3) and summer it runs early and late.

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Blurtie

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#2229534 2-May-2019 16:03

Thanks for all the responses so far guys.

We've got partial wall insulation round the house, but the main bedrooms haven't been done. I intend on doing this at a future date when I have more time and resources. But to me, the time and effort (and cost to a lesser degree) of doing this doesn't stack up to the immediate benefit I would get by installing a ducted heat pump. Same could be said for double glazing.

In an ideal world, yes, I'd love nothing more than to have my house fully insulated and double glazed, but with the amount of money required to get this does done, i'm not totally convinced that this is where I should start?

@jonathan18 thanks for forwarding that link, I have read that thread a while back, but good to read it through again. Looks like my situation is very similar to what you had. Would be interested to know if your house had condensation issues prior to installing your system and what it's like now? Interesting to read your take on the zones and how you don't use them, is this still the case?

In terms of condensation, I don't think it's that bad, I mean it's not dripping wet or anything like that, but it is there.. the worst of it is probably in the dining/kitchen room in the morning. But turning on the dehumidifier for an hour or so gets rid of it. I should add that that part of the house faces west, so gets good afternoon sun and is usually noticeably much warmer than the east facing bed rooms when we get back in the evening after work. The other heat pump is in the dining area and hence doesn't get used as much.

When we got the quote, we had a guy come and actually size up our place and he didn't think it would be an issue installing the system in the roof space. I think he mentioned that he would just push it through the return. But would be interested to hear what you guys think of his comment that older houses "breathe naturally and provide fresh air into your home" so no ventilation unit required for now... seems plausible to me...

Blurtie

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#2229535 2-May-2019 16:09

As for PVC/Aluminium double glazing, we're not big fans. So definitely expecting costs for us to get double glazing of our windows to be higher than the figure quoted by timmmay..

Cody64

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#2229541 2-May-2019 16:33

Having a ducted system in our house, I can thoroughly recommend it however it is a new house with double glazing so I don't know how effective it would be in your case. Do you have good thermal drapes? We notice even with double glazing the air behind the curtains is cold so the curtains prevent the heat loss there.

Our ducted system is zoned, but we have never turned any off, as the one thing we love is that all the rooms are the same temp. We don't shut doors in rooms we aren't using like we used to in our previous houses. Fitting the indoor unit would most likely involved lifting the roof. Our unit is rated at about 14Kw and adds about $100 - $150 per month to the power bill but it is running 24/7 during winter.

Aredwood

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#2229665 2-May-2019 18:54

Blurtie:
But would be interested to hear what you guys think of his comment that older houses "breathe naturally and provide fresh air into your home" so no ventilation unit required for now... seems plausible to me...

Old houses definitely breathe alot already. As they were simply never designed or intended to be airtight.

Note also, that the larger the temp difference between inside and outside. The faster they will “breathe”. (more leakage of warm air to outside due to draughts).

Definitely fix your heating problems/ insulation problems first. Before installing any dedicated ventilation system. As you will be getting more ventilation whether you like it or not, once you are able to keep the house warm.

Of course still install a kitchen range hood and bathroom extractor fan if you haven't already.

Dehumidifiers also give you 0.6KW/Hr of free heat, for every liter of water they remove from the air. So definitely use them in areas that you currently have electric resistance heaters.

Wheelbarrow01

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#2229723 2-May-2019 19:59

I have a 1960's brick veneer house (circa 120m2) which I bought in 2015. At the time it had one heatpump in the lounge, no wall insulation, and no/very little ceiling insulation in the cathedral ceiling area of the kitchen/lounge. The rest of the house with normal flat ceilings seems to have good insulation. The windows are all double glazed but not thermally broken, and there's foil insulation under the timber floor.

When my first winter in 2016 rolled around, I froze my butt off. The heatpump did virtually nothing but my power bill still went through the roof. I had it running set to 27 degrees but the house barely got over 18. By October that year I had had enough, so I was happy to pay $7500 for a Masport ULEB log burner to be installed.

This improved things significantly and made the house very comfy (and instantly cut the winter power bill by over 75%) but I still noticed in the 2017 winter that once I let the fire go out each night, the house would be freezing cold again within about an hour.

So mid 2017 I paid another $5000ish for dry blown insulation to be installed in all the walls. They drilled holes in mortar joints between the bricks, then blew the insulation in under pressure so that it was tightly packed in the walls. they then mortared up the holes and job done. Thermal imaging cameras used during the installation ensured that no gaps were left. At this time I also insulated and re-lined the cathedral ceilings in the kitchen/lounge area. The insulation product used in the walls is water phobic, breathable and will not wick, and comes with a 50 year guarantee.

The difference post insulation installation was instant and amazing. Now I only run the fire for an hour or two per night in winter, and the house stays comfortably warm until morning. We are with Electric Kiwi for power so I use our hour of free power from 6-7am every day in winter to turbo heat the house with the heatpump free of charge on cold mornings. I got a 3 room heat transfer kit free with the fire, however I still haven't installed it yet (it's on the to-do list!). I currently use a large desk fan on the hallway floor which pushes colder air from the bedrooms and hallway into the lounge and you can feel warm air being pushed back down the hall at head height - a MacGyver solution which gets me by for now lol.

We still get a little bit of morning condensation - mostly on the floor to ceiling windows in the lounge, but I combat this with a dehumidifier which runs a few hours a day in winter, alternating it between the lounge and hallway. The house takes advantage of thermal gain during the day so is still reasonably warm when I get home on sunny winter days.

So for around $12,500 I have completely transformed the house from almost unbearable in winter to supremely comfortable. I now use around 3 cubic metres of firewood ($330) per year, and our winter power bill is now pretty much the same as summer - around $120/month. That first winter I was getting $500 bills over the winter months.

Other than finally installing the heat transfer kit, the only other thing I'd like to do is put a vapour barrier on the dirt under the floor which may help with the residual condensation.

I think I have done alright - $330 for around 5 months of winter heating seems like pretty good value to me.

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timmmay

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#2229737 2-May-2019 20:12

I don't recommend pumping insulation into walls if they have to drill through. I think it can go through the waterproof barrier and cause moisture issues if weatherboards have any gaps.

When I had the walls insulated I didn't notice much difference at all, whereas double glazing and putting in extra ceiling insulation made a big difference. A ground sheet and under floor insulation helped the smell and dampness and the heat a bit. So I guess weatherboard houses get less benefit from wall insulation than brick.

Fires are also really antisocial in residential neighborhoods. One fire lit means potentially dozens of houses get filled with smoke or have to close windows and turn ventilation systems off. They're bad for breathing problems too. I reckon they should be banned.

shk292

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#2229741 2-May-2019 20:16

timmmay:

Fires are also really antisocial in residential neighborhoods. One fire lit means potentially dozens of houses get filled with smoke or have to close windows and turn ventilation systems off. They're bad for breathing problems too. I reckon they should be banned.

Isn't that the idea of ULEB, ie it doesn't cause those problems?

mdf

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#2229746 2-May-2019 20:24

timmmay:

I don't recommend pumping insulation into walls if they have to drill through. I think it can go through the waterproof barrier and cause moisture issues if weatherboards have any gaps. <snip>

I was in this camp too, until I saw the videos that @wheelbarrow01 linked to in his previous thread. Seems like super clever stuff, and it has the NZ Codemark certificate. Brick house in that case though so no wrap/building paper.

mdf

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#2229755 2-May-2019 20:40

For the OP's initial queries, does Christchurch have the equivalent of Wellington's Sustainability Trust - I've found they provide excellent independent(ish) advice about best bang for buck.

Probably the main query is how long you plan to be in the house. If it is the forever/long term home, any investment now will be worthwhile in both financial and comfort payoffs. If you're only planning on staying for a few years, I wouldn't go to big expense.

IME:

- Central heating is great, but expensive to install. There are brands that include external fresh air ventilation, eg. Mistubishi Lossnay. For roof installs, the main unit usually comes in parts sized for a standard manhole cover and assembled in the attic. Depending on the system, you can set up zones. If you wanted this, I would insist on a demonstration of how this works. We've got the gas central heating equivalent and the controls are super dumb so I end up walking around the house a couple of times a day adjusting the settings.

- If you've already got heatpumps that go okay, I suspect you can get much more bang for buck elsewhere than central heating though.

- Fresh air ventilation (probably positive pressure for you) will have a positive impact on quality of internal air and isn't that expensive to install.

- Heat transfer kits can work quite well to make places like bedrooms more comfortable. I'm pretty sure there is a system (maybe smartvent?) that does fresh air and heat transfer.

- If you can double glaze a whole house for $10K, I am getting completely ripped off. We're doing a few windows at the moment and while they are large and at the more premium end of the spectrum, $10K got us 5 windows.

- In roof insulation is best bang for buck around. Do you know the R-rating or depth of what you've got? Adding a bit there might help too.

- In wall insulation (potentially with thermal curtains or aircell blinds over non-double glazed windows) can provide huge benefits. You won't do a house for your budget, but you might be able to come up with a room-by-room plan over the next few years. Don't know about Chch building consent rules, but you can get a multi-stage building consent in Wellington (not sure that's the right term).

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