Double Glaze / Old windows

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timmmay

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#1571644 14-Jun-2016 13:44

chimera:

Totally agree. I got an HRV. It actually is great for ventilation - but only at certain times of the day. Later at night when you're trying to warm the house by some alternate means, the HRV is blowing typically cool air from the ceiling around the house. Completely counter intuitive. What it needs is a heat pump/aircond unit on the HRV intake for winter/summer use. Just using ceiling cavity air (which is sucked in from outside) is a total waste of time, its either too cold in winter or too hot in summer. I'm graphing all this information at present to determine the optimal heating solution for my own home (including searching aliexpress for heat exchange units that may work with the HRV!)

The funny thing about this is HRV stands for "heat recovery ventilation", I think HRV sells them but they cos tmore. Blowing smelly, cold ceiling cavity air into the house is almost never the right option. Pulling in fresh, cooler air, running it through a heat exchanger, you'd be a lot better off. Cleanaire might sell you a heat exchanger.

Oriphix:

This is awesome. I might give that a go.

The main reason I was looking at double glazing is our house windows gets fully wet (the whole house). We have only recently bought the house in it about 6 months.

Didn't notice anything till it started to get cold. It does have bats in the roof but I guess we can put another layer it won't cost that much.

But I guess retro fitting the windows might be a cheaper alternative if you didn't notice double glazing did that much difference.

We don't have a heating solution for the house currently which we need to think about as well.

Sounds like you need both ventilation and heating. You'd be better off getting an integrated unit up front than doing what I did, buying the bits separately, then releasing it'd be better if they worked together.

For now, try opening the windows for a half hour a day, ideally earlier in the day, to reduce moisture levels. Make sure you have suitable extraction. If you have windows you can lock open leave them slightly open unless rain will actively come inside.

Proper heat recovery ventilation will reduce wet windows, as will double glazing, but you probably need both for an actual solution.

chimera

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#1571664 14-Jun-2016 14:07

timmmay:

Blowing smelly, cold ceiling cavity air into the house is almost never the right option.

In their defense, I think "smelly" isn't quite the right word. They use an exceptionally fine filter at the intake, so the air is exceptionally fresh when pumped around the house.

timmmay

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#1571676 14-Jun-2016 14:15

chimera:

timmmay:

Blowing smelly, cold ceiling cavity air into the house is almost never the right option.

In their defense, I think "smelly" isn't quite the right word. They use an exceptionally fine filter at the intake, so the air is exceptionally fresh when pumped around the house.

That may just be mine, but in my very old house with a standard filter there was definitely an odor.

langers1972

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#1571677 14-Jun-2016 14:16

Willuknight:

I'm probably going to be in this house minimum 10years, not planning on moving any time soon.

The house currently has a non working airflow system that takes heat from the lounge with the woodburner and vents to all the bedrooms. I think all I need to do is replace the main unit to use that. Even if I can't get that system back up, my idea with the double glazing is that once you heat up your room, the room will retain heat, so rather than leaving a heater on, you can warm up the room and it will stay nice for the rest of the evening. It's definately already better than my old house in that once you're in bed and it's warmed up, you don't freeze to death.

My current plan is:

1) Take care of heat loss

- double glazing
- floor insulation
- 2nd blanket on roof insulation

2) fix DVS

I would flip your list on it's head, you lose far more heat through the walls and ceiling than the windows PLUS even the best double glazing only gives you an R value of just above 1 whereas you can bump up your roof, underfloor and walls to way more than that (we have R5+ in the roof with 2 layers of insulation running across each other in a weave to stop heat loss through the joists)

Underfloor can be over R2 so still double what you'll get with double glazing (BTW we also double glazed the entire house so I am not anti DG!)

langers1972

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#1571680 14-Jun-2016 14:21

chimera:

Clearly the biggest gain will be a heat pump. It's entire purpose is to generate heat - everything else discussed are simply insulators and there purpose is to retain heat/minimise heat loss - its not an apples vs apples comparison - an appliance that generates heat will outweigh anything else you do to any area of the house. I'm simply discussing the insulating side of the equation.

Completely disagree, there's no point spending money on a 'heat generating machine' if you've no means of keeping that heat in the house, you may as well set light to $20 notes to keep warm. Kiwis have been sold a line that heatpumps are the silver bullet but they're just a modern replacement of the single source of heating in the house that was a log burner in the past. Much better ROI to keep passive heat in first and THEN spend money on heating.

timmmay

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#1571689 14-Jun-2016 14:29

langers1972:

chimera:

Clearly the biggest gain will be a heat pump. It's entire purpose is to generate heat - everything else discussed are simply insulators and there purpose is to retain heat/minimise heat loss - its not an apples vs apples comparison - an appliance that generates heat will outweigh anything else you do to any area of the house. I'm simply discussing the insulating side of the equation.

Completely disagree, there's no point spending money on a 'heat generating machine' if you've no means of keeping that heat in the house, you may as well set light to $20 notes to keep warm. Kiwis have been sold a line that heatpumps are the silver bullet but they're just a modern replacement of the single source of heating in the house that was a log burner in the past. Much better ROI to keep passive heat in first and THEN spend money on heating.

The context for this statement is that the house already has ceiling insulation, but not under floor, wall, or double glazing. Most heat is lost through the ceiling. As such a heat pump will make the house a lot warmer and will retain a lot of the heat generated. Adding wall and floor insulation will help a bit, but my guess is it will reduce the heating bill without making the place a lot more comfortable. I suspect extra ceiling insulation would be the biggest win. I wouldn't say more insulation is essential before getting a heat pump, because right now heating with conventional heating just means they need to generate heat and it's costing more.

MikeAqua

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#1571701 14-Jun-2016 14:40

We put a Smart Vent proper heat recovery ventilation in our last house. I.e. a system that puts outgoing and (filtered) incoming air through an air to air heat exchanger. Great decision.

You could feel the reduction in moisture in the air and in fabric (furniture, bedding etc). Condensation (single glazing) all but vanished. Furniture felt warmer to sit on. We were able to reduce the temperature set points on our heat pumps. Although the system uses a 150W fan (variable speed) our power bills actually decreased. I put that down to drier air feeling warmer and being easier to heat.

Mike

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Willuknight

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#1571756 14-Jun-2016 15:45

Oriphix:

Willuknight:

What are people's thoughts on retrofitting? I have a big house with lots of big single glazed aluminium windows. Roof and walls are insulated. None of the windows have the boxes above the curtains to prevent air seeping in and non of the curtains are floor length.

I've been quoted $6000 to do all the bedroom and living area windows, seems like the best thing to spend money on as windows will be my biggest heat loss?

Can you give me the company you used for a quote?

I was also exploring this option.

SC Retro. Pretty prompt. Small company. Came recommended from a business associate who had her house done and was very happy. Christchurch only.

021 925211

Oriphix

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#1571759 14-Jun-2016 15:48

timmmay:

Sounds like you need both ventilation and heating. You'd be better off getting an integrated unit up front than doing what I did, buying the bits separately, then releasing it'd be better if they worked together.

For now, try opening the windows for a half hour a day, ideally earlier in the day, to reduce moisture levels. Make sure you have suitable extraction. If you have windows you can lock open leave them slightly open unless rain will actively come inside.

Proper heat recovery ventilation will reduce wet windows, as will double glazing, but you probably need both for an actual solution.

Do you have any recommendations on a integrated unit?

chimera

506 posts

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#1571789 14-Jun-2016 16:17

langers1972:

chimera:

Clearly the biggest gain will be a heat pump. It's entire purpose is to generate heat - everything else discussed are simply insulators and there purpose is to retain heat/minimise heat loss - its not an apples vs apples comparison - an appliance that generates heat will outweigh anything else you do to any area of the house. I'm simply discussing the insulating side of the equation.

Completely disagree, there's no point spending money on a 'heat generating machine' if you've no means of keeping that heat in the house, you may as well set light to $20 notes to keep warm. Kiwis have been sold a line that heatpumps are the silver bullet but they're just a modern replacement of the single source of heating in the house that was a log burner in the past. Much better ROI to keep passive heat in first and THEN spend money on heating.

Yeah as mentioned above, you missed the context of that post. A heat pump will generate more heat than having an insulated ceiling, that's just a plain fact. The heat loss as I already mentioned and you also eluded too, will be obviously greater without the insulation. So yes, I agree with insulating first then going to a heating appliance, however the context of the earlier conversation was more around whether double glazing windows was worth the cost eg: whether he would, post decent roof/ceiling insulation and decent curtains/blinds, be worth while going to double glazed windows for $6k or installing a heat pump or heating recovery system for similar or less.

timmmay

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#1571792 14-Jun-2016 16:26

Oriphix:

Do you have any recommendations on a integrated unit?

Best talk to a company who specialises, may or may not be practical or economic. Wasabi Air in Wellington are worth talking to. Mitsubishi Lossnay is one option. Another is just having a large heat pump, sized for the house, and a heat recovery ventilation system (not specially HRV brand).

1eStar

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#1572300 15-Jun-2016 12:23

be warned: most HRV systems 'recover' heat from the ceiling space (which doesnt exist in winter). Very few systems have a heat exchange unit to actually recover heat energy from the interior of your house.

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