Insulation for new house build

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#1465763 8-Jan-2016 11:50

nofam: (cut) I'm only talking about a kitchen/living room/foyer, so it's probably only 70 m2, and I'm not worried about it being toasty enough in winter to walk around in bare feet. I totally get hydronic heating for whole house, as it's eminently sensible, but I struggle with the cost for the benefit of 1/3 of the house. As mentioned, my primary interest in concrete is for the aesthetic aspect, followed by easy cleaning etc.

I may be a stuck record on this but I'd like to reiterate that I (and clearly many others on this forum) think you're taking a significant risk in not putting in underfloor heating, at least in the area where you'll have exposed concrete floors.

Have you experienced what such a floor feels like in the depths of a Dunedin winter? I wouldn't rely on anything I've read or been told about how insulating/isolating a slab makes it ok warmth-wise, as once you've NOT done it there's no retrofitting possible!

As others have also pointed out, if you don't at least provide the pipework for such heating there is a significant risk you'll impact on the potential resale value of the house, when/if you come to sell. I know many people (including myself) that wouldn't contemplate buying a house like that, even in a warmer climate let alone Dunedin.

Surely in the grand scheme of the significant costs of building a house you can cut some corners elsewhere to at least future-proof the house in this way?

Personally, I can't wait for the trend of polished concrete floors to end (aesthetically cold and sterile), but if you're gonna do it do it properly I reckon!

nofam

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#1465975 8-Jan-2016 15:52

jonathan18:
nofam: (cut) I'm only talking about a kitchen/living room/foyer, so it's probably only 70 m2, and I'm not worried about it being toasty enough in winter to walk around in bare feet. I totally get hydronic heating for whole house, as it's eminently sensible, but I struggle with the cost for the benefit of 1/3 of the house. As mentioned, my primary interest in concrete is for the aesthetic aspect, followed by easy cleaning etc.

I may be a stuck record on this but I'd like to reiterate that I (and clearly many others on this forum) think you're taking a significant risk in not putting in underfloor heating, at least in the area where you'll have exposed concrete floors.

Have you experienced what such a floor feels like in the depths of a Dunedin winter? I wouldn't rely on anything I've read or been told about how insulating/isolating a slab makes it ok warmth-wise, as once you've NOT done it there's no retrofitting possible!

As others have also pointed out, if you don't at least provide the pipework for such heating there is a significant risk you'll impact on the potential resale value of the house, when/if you come to sell. I know many people (including myself) that wouldn't contemplate buying a house like that, even in a warmer climate let alone Dunedin.

Surely in the grand scheme of the significant costs of building a house you can cut some corners elsewhere to at least future-proof the house in this way?

Personally, I can't wait for the trend of polished concrete floors to end (aesthetically cold and sterile), but if you're gonna do it do it properly I reckon!

As a matter of fact, I have - my inlaws have a house in the same subdivision as our section, and their living area and master bedroom is wood-effect karndean vinyl over insulated concrete (the house is built for paraplegic access). Their floor has never felt 'cold' - I certainly wouldn't say it was warm, but their living area/kitchen/lounge is heated by a single heat pump and has never felt anything like cold over this winter. They have no edge insulation, nor would they have as much solar gain as we will, and don't have low-e glass, just argon filled, thermally broken joinery. . .So you can see my reluctance.

Don't get me wrong, I'll certainly be getting quotes for the heating, hence why I wanted some debate, and challenge to my thinking!!

Jase2985

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#1465996 8-Jan-2016 16:01

vinyl ≠ concrete

completely different heat transfer and insulation properties

you cant compare.

SumnerBoy

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#1466002 8-Jan-2016 16:11

I would agree with jonathon - if you are doing a concrete slab you should definitely put pipes in the slab - it is only a few hours labour, and the pipe is cheap, and then at least you have the option. IMO all concrete slabs should have this as standard/mandatory.

nofam

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#1468970 13-Jan-2016 10:35

Thanks for all the debate/suggestions guys - have contacted the local installer for Sunflow systems to give me a quote for a full system to heat the living area/kitchen/foyer as well as the bathroom/toilet floors. Depending on the solution proposal, I might also look at heating the hot water for the house with the same system. I've also asked them for a price to just install the pipework for future-proofing.

Will keep you posted!

Nikoftime

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#1468984 13-Jan-2016 10:58

these Dunedin guys might be worth talking with

http://www.upvcwindows.co.nz/services/services

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bfginger

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#1475015 20-Jan-2016 06:21

Planitherm low-e glass is a brand and family of products and not a specific product. So your quote should say which kind of Planitherm you're buying as they have different qualities. Why do you have low-e glass in the living area but not the bedrooms?

Low-e glass reduces solar heat gain compared with plain and high clarity glass so it's less use in north facing windows that are shaded in summer. There is a hit to light quality from low-e glass but it makes a large difference to the insulation value. Ideally low-e glass should be the high solar gain type but I don't think the local glass companies do it. Plastic spacers inside the glazing unit should transfer less heat than aluminium spacers.

Investigate low-e triple glazing for south facing windows but I think only Fairview/Elite do an aluminium profile wide enough for it in New Zealand. I recommend multi-point locking as the single point window latches aren't very effective. If you plan on getting sliders check the effectiveness of the profile's seals as some aren't very airtight.

With Dunedin's climate the more insulation the better. The standard insulation put in walls in New Zealand is only R2.2. For a 9cm external wall cavity you could boost that to R2.8 with Pink Batts or R2.5 with wool-polyester. For a 14cm cavity you could respectively get R4.0 or R3.5. Have someone checking the site when it's installed so they don't install R2.2 by mistake.

I would go for R6 or more in the ceiling like double layer 3.0 to 4.0, or single layer R7.0 pink batts which should work like R6 with joists and thinner insulation on edges to clear the roof lining.

uPVC is used so much in Europe because it's cheaper in that market. If thermally broken aluminium was cheaper they would use that. Companies that sell uPVC aren't the ones to listen to about aluminium windows. I'd expect service life for new aluminium windows to be longer. Aluminium and more so uPVC will expand and contract with temperature changes so their lifespan or the lifespan of the glazing unit may be reduced if they aren't a light colour.

As the window frame is only a small part of the window it isn't a big influence compared with the glass unless you get something like a metal window without a thermal break which will act like a heatsink. Maximising frame performance is more important in a place like Central Otago or Canada.

A heat reclaim ventilation system would distribute warm air more evenly around the house. Some systems don't recover heat very well so you need to be careful. Theoretical maximum and actual performance aren't the same.

This is where size/length of Eaves do the magic. This is the hard part. Calculating the right size/length of eaves required to block sun in summer when it's higher but allow sun in winter when it's lower.

Something manually adjustable is the ideal. For November in particular.

Does the expense of low e, and argon filled glass outweigh the savings you would make in heat loss? As a lot of the heat is still out the windows, you can actually reduce the heat loss more by reducing the window sizes.

Standard double glazed glass is R0.35, with argon it's R0.4, quality low-e with argon can take it as high as R0.91.

Air gap thickness between glazing will affect performance

https://windows.lbl.gov/adv_sys/hi_R_insert/GapWidths.html

timmmay: http://ohp.parks.ca.gov/pages/1054/files/uk%20window%20frame%20lca.pdf

Re: underfloor heating, one of our soon-to-be neighbours has built and put this in - he's spent the thick end of $40k on the heating system, and has $700 a month power bills.

Pipes straight into the slab with no edge insulation? It is possible to retrofit slab edge insulation. 80% of heat loss from a concrete slab is on the edges so having slab edge insulation is far more important than insulation under the slab. Won't wood in the ground just rot? Overseas they put the pipes between the flooring and concrete, which should be more retrofittable.

richms

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#1475083 20-Jan-2016 08:53

I was told that there is a problem with putting pipe in just for futureproofing as when its not in use it is prone to collapsing, so check that out with the guys putting the pipes in that it will be all good being left without pressure in it for years.

Richard rich.ms

nofam

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#1475140 20-Jan-2016 09:52

bfginger: Planitherm low-e glass is a brand and family of products and not a specific product. So your quote should say which kind of Planitherm you're buying as they have different qualities. Why do you have low-e glass in the living area but not the bedrooms? Low-e glass reduces solar heat gain compared with plain and high clarity glass so it's less use in north facing windows that are shaded in summer. There is a hit to light quality from low-e glass but it makes a large difference to the insulation value. Ideally low-e glass should be the high solar gain type but I don't think the local glass companies do it. Plastic spacers inside the glazing unit should transfer less heat than aluminium spacers. Investigate low-e triple glazing for south facing windows but I think only Fairview/Elite do an aluminium profile wide enough for it in New Zealand. I recommend multi-point locking as the single point window latches aren't very effective. If you plan on getting sliders check the effectiveness of the profile's seals as some aren't very airtight. With Dunedin's climate the more insulation the better. The standard insulation put in walls in New Zealand is only R2.2. For a 9cm external wall cavity you could boost that to R2.8 with Pink Batts or R2.5 with wool-polyester. For a 14cm cavity you could respectively get R4.0 or R3.5. Have someone checking the site when it's installed so they don't install R2.2 by mistake. I would go for R6 or more in the ceiling like double layer 3.0 to 4.0, or single layer R7.0 pink batts which should work like R6 with joists and thinner insulation on edges to clear the roof lining. uPVC is used so much in Europe because it's cheaper in that market. If thermally broken aluminium was cheaper they would use that. Companies that sell uPVC aren't the ones to listen to about aluminium windows. I'd expect service life for new aluminium windows to be longer. Aluminium and more so uPVC will expand and contract with temperature changes so their lifespan or the lifespan of the glazing unit may be reduced if they aren't a light colour. As the window frame is only a small part of the window it isn't a big influence compared with the glass unless you get something like a metal window without a thermal break which will act like a heatsink. Maximising frame performance is more important in a place like Central Otago or Canada. A heat reclaim ventilation system would distribute warm air more evenly around the house. Some systems don't recover heat very well so you need to be careful. Theoretical maximum and actual performance aren't the same.
This is where size/length of Eaves do the magic. This is the hard part. Calculating the right size/length of eaves required to block sun in summer when it's higher but allow sun in winter when it's lower.
Something manually adjustable is the ideal. For November in particular.
Does the expense of low e, and argon filled glass outweigh the savings you would make in heat loss? As a lot of the heat is still out the windows, you can actually reduce the heat loss more by reducing the window sizes.
Standard double glazed glass is R0.35, with argon it's R0.4, quality low-e with argon can take it as high as R0.91. Air gap thickness between glazing will affect performance https://windows.lbl.gov/adv_sys/hi_R_insert/GapWidths.html timmmay: http://ohp.parks.ca.gov/pages/1054/files/uk%20window%20frame%20lca.pdf
Re: underfloor heating, one of our soon-to-be neighbours has built and put this in - he's spent the thick end of $40k on the heating system, and has $700 a month power bills.
Pipes straight into the slab with no edge insulation? It is possible to retrofit slab edge insulation. 80% of heat loss from a concrete slab is on the edges so having slab edge insulation is far more important than insulation under the slab. Won't wood in the ground just rot? Overseas they put the pipes between the flooring and concrete, which should be more retrofittable.

Thanks for the comments @bfginger:

- From memory, it's Planitherm XN, and I was incorrect - all windows on that side of the house would be low-e
- All external walls are 140mm framing, so R-values will be 4.0 in the external walls, 2.8 in internal walls and 7.0 in the ceiling
- I need to discuss with the builder, but I'm thinking of doing ICF footings for the areas with exposed concrete to achieve slab-edge insulation. However I achieve this, it'll be designed so it can be plastered over to match the rest of the exterior

BTR

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#1475255 20-Jan-2016 12:04

When I renovated my lounge I put R2.8 batts and a sheet of noise-line Gib on that wall and it made a HUGE difference.

I have since read that I did;t quite install the Gib correctly and that it should have been installed on special braces that reduce the amount of vibration coming off the Gib and onto the framing but also that you are supposed to install 2 sheets thick and have the joins in each layer overlapped and edges sealed using a special sealant although this seems extreme

I am happy with the install that I did and would recommend both noise cancelling Batt and Gib.

nofam

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#1475984 21-Jan-2016 11:16

So I have a quote back from a local outfit that specialise in underfloor heating solutions, and it's very reasonable:

- 6.2 kW Heatpump unit
- 250L stainless steel HWC (this system will also provide all domestic hot water via a diversion control)
- Heating for polished concrete areas (Living Room, Entrance, Kitchen) - Zones 1, 2 & 3
- Heating for bathroom, WC and ensuite - Zone 4
- Heating for hallway (carpeted), with piping runs slightly into bedroom 2, 3, and 4 - this removes the need for a heatpump in the hallway - Zone 5
- Controlled via the manifold and/or a heatpump master control panel
- Slab & air-temp probes x 2
- Pipe is Poly oxygen barrier, rather than standard PEX to reduce risk of corrosion

Price for supply and installation of the above is $13196. As mentioned, I'd planned on a heatpump for both the living area and hallway - think I'll still opt for the living area one, as there will still be days where the room needs an immediate lift in temps.

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timmmay

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#1476058 21-Jan-2016 12:28

6.2kw isn't huge, but might be enough for a modern house. Will it just be for hot water? That's different from air / space heating. If you can have a heat pump under floor heating unit so it does most of its heating at night, and go on Flick electric, your bills should be pretty reasonable.

In my very old but reasonably well insulated house (lots of insulation, some double glazing) I have 10kw in the lounge / bedroom area and 7kw in the kitchen / dining area. One might be able to do the whole house, if it was left on all the time, and airflow allowed it.

nofam

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#1476144 21-Jan-2016 13:58

timmmay:

6.2kw isn't huge, but might be enough for a modern house. Will it just be for hot water? That's different from air / space heating. If you can have a heat pump under floor heating unit so it does most of its heating at night, and go on Flick electric, your bills should be pretty reasonable.

In my very old but reasonably well insulated house (lots of insulation, some double glazing) I have 10kw in the lounge / bedroom area and 7kw in the kitchen / dining area. One might be able to do the whole house, if it was left on all the time, and airflow allowed it.

Yes, just hydronic underfloor heating and the hot water for kitchen/bathrooms/toilets and laundry. The total area being heated hydronically is ~112m2, so it's not massive, and with the R-values I'm proposing there should be minimal heat loss - based on the thermal envelope, the vendor has stated it's not even necessary to consider heating the whole house.

And yes, I'll definitely be looking at a day/night meter and plan; should be able to get a night-rate of 13cpkw vs 24 or so?

timmmay

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#1476160 21-Jan-2016 14:25

nofam: Yes, just hydronic underfloor heating and the hot water for kitchen/bathrooms/toilets and laundry. The total area being heated hydronically is ~112m2, so it's not massive, and with the R-values I'm proposing there should be minimal heat loss - based on the thermal envelope, the vendor has stated it's not even necessary to consider heating the whole house.

And yes, I'll definitely be looking at a day/night meter and plan; should be able to get a night-rate of 13cpkw vs 24 or so?

Sounds like a good plan. Overnight power can be as cheap as 9c/kwh.

Shab

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#1495030 18-Feb-2016 15:36

billgates: If you are doing polished concrete floors for north facing area then consider underfloor heating specially in South Island where it's much more colder. Unless you get a lot of sun and have some big Windows to let in a lot heat and have it blocked by Low-E glass from escaping in your North then polished concrete might not retain a lot of heat.

I am going through the same exercise as you and almost near the final design phase doing 2.7m stud on ground floor and 2.55m first floor with thermally broken, argon filled and Planitherm low-e everywhere. Cladding is also Rockcote Integra 50mm. I am going with Knauf R5.2 for ceiling insulation and R3.6 for wall insulation with R3.2 for midfloor insulation. Getting all bedrooms, home cinema double stud walls, toilets, bathroom, laundry and garage insulated as well.

Noise reducing batts and noise reducing GIB are not as effective as the marketing material states. Your standard R3.6 insulation will do just as well job of blocking some sound as noise batts for cheaper.

In order to reduce noise between rooms there are few different methods of room constructions you could look at. For me, the only room that will produce the most serious amount of noise is the home cinema room and I am making that a double stud wall construction with R3.6 wall insulation in both stud walls followed by 2x 16mm layers of Fyreline GIB on both side of stud walls with green glue (Importing from US) between this. For my entire house ceilings I have also added GIB STWC Acoustic clips to which the batten will connect to. Home cinema will however also have 2 x 16mm Fyreline GIB with green glue in between on top of this along with sealed and sound proofed solid core entry doors (x2).

Have a good read of few of the Sound Proofing Company articles below. The PDF below is a very simple to understand 11 page document on basics of sound proofing. Unless you are looking at spending few $$$ per room, you will not get absolute sound proofing from any of the rooms and this includes getting solid core doors with jamb seals etc. Sound will find a way to travel and leak and that could be from walls, ceilings and even the floor. Double GIB will be a step and be somewhat effective specially if you use green glue in between this else just stick to standard GIB with insulation between rooms which will block non speakers/sub woofers firing related noise in the bedrooms.

http://www.woodworks.org/wp-content/uploads/Acoustics_Solutions_Paper.pdf

http://www.soundproofingcompany.com/soundproofing-solutions/soundproofing-walls/

You can buy that Green Glue locally at www.greenglue.nz

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