Heating for SIP construction home
Posted 01 Sep '19 08:18 PM
Hi all. We are planning to build a SIP home single level approx 150sqm and wondering what type of heating would be suitable. We're on South East facing beach front section in dunedin.
We have been looking at 11kw woodburner and possibly built in panel heaters in bedrooms. Just not sure what to expect in terms of hearing requirements.
Posted 02 Sep '19 04:30 PM
That depends on a number of different things, how airtight the house will be, level of insulation in the SIPs, windows, roof, floor, if you're having an energy recovery ventilation system, whether you like cutting firewood, whether you're having an PV on the roof etc.
Typically with more airtight houses, you may need a dedicated air feed/supply to any woodburner to keep it working efficiently.
It may be worth 'uping' the spec on the house to reduce heating load.
If you're wanting a definitive answer, having the house modelled by a professional will tell you exactly how much heating you'll need.
Anyone who designs passive or certifies passive houses, or uses WUFI should be able to do the modelling .
Posted 17 Sep '19 10:52 AM
I second this comment. There are far too many unknowns to provide a useful response. SIP construction in of itself does not necessarily mean well insulated, well sealed, minimal thermal bridges, good solar design, and efficient ventilation. I'm in the south-west North Island (NIWA classification) where winter daytime maximums are typically in the range 10°C to 14°C (Dunedin is 8°C to 12°C). Heating and cooling for 166 m² is provided with one small heat pump (750W consumption, 3.4kW heating, 2.5kW cooling) and ventilation with a primitive HRV (the technology, not the brand). The house is well insulated, well sealed, and makes effective use of the Sun. If you're doing a high thermal efficiency build, my guess is that an 11kW wood burner may rapidly overheat the house.
But, it all depends on the details. Having the house modelled is an excellent suggestion.
Posted 26 Sep '19 09:45 PM
We are also planning on building a similar sized SIP house (concept stage) and at the early stages of thinking about heating. We were originally thinking of an in-slab wet system, but the house design is upside down with bedrooms downstairs so concerned about the majority of the heat being downstairs when we want it upstairs. Slab heating is hard to control, so overheating in the wrong portion of the house is a real possibility. Perhaps best idea to consider really responsive heating like a well placed heat pump. Agreed that an 11kw would be at risk of overheating.
Posted 10 Oct '19 08:29 PM
Hi there we have just built a Forman sips 150m2 home in Dunedin with views to the South/East in Brighton and have been in for 6 months. We are on a pile floor and have a 11kw Ethos fire only to heat the house. It is all we have used for heating. Feel free to come have a look you can contact me on 0272219080. Cheers Ben
Posted 10 Oct '19 09:33 PM
Our house is a 2 storey Formance SIPs house located on the Port Hills in Christchurch. The walls are 165mm, roof (skillion) 215mm (+R2.2 Earthwool between the panels and ceiling), expol under the timber floor, uPVC windows and doors and 0.48 ACH.
We have just completed our first winter in the house. The only heating in the house is 3 plug-in oil column heaters (1x 2kW & 2x 1kW). Our bedrooms are downstairs and the house is positioned for east and north solar gain so we only needed to use the heaters on cloudy days.
We made it to June 1 before we had to switch the heaters on and our space heating costs were $240 for June 1 - September 30 period.
Posted 10 Oct '19 09:41 PM
Sounds good. The feedback from SIP house owners seems to always be positive.
I made the comment that 11kw heater might overheat. Do you have this issue, or if you do, whats the solution? Open a window?
Posted 11 Oct '19 08:52 PM
Our fire is rated at 18kw max. To paint a picture of the home it’s essentially 5mts wide and 30mts long the fire is at one end of the house. We have an open hallway that runs the length of the house with 4 bedrooms bathroom etc coming off it. The fire to us has been great over winter and haven’t felt the need for anymore heating throughout the house we normally just get it going then turn it to the lowest setting. Yes we have had a little overheating when the fire is on and the sun comes out so we do as you said and open the sliding doors or a couple of windows. We normally bank the fire at night go to bed at around 23-24 degrees and wake up to 19-20 degrees.