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Co-Heating Test

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I was grazing over my twitter feeds and came across a reference to Co-Heating which was new to me! Most of us are familiar with the blower door test for air tightness but this one wasn't one I'd heard of before! 


Basically they set up coil heaters and fans, open all interior doors and measure room temperature vs outside sensors to determine if the house performs as it should (keeps the heat in as per calculations based on building type, materials and insulation depths etc, and releases it as projected). They recommend 1 - 2 weeks of data (3 days to setup and tweak). 


It's interesting as it addresses building performance like airtightness tests do. There's currently doubt over the test as shown below so hopefully over time a better standard will emerge. 


Would I get one done? If I was buying a developer built house, I'd certainly consider it. It should be forced on every developer for every house they build! For Self-Build with PHPP in place I'm less worried. You should still keep a close eye on things with a few trusted professionals to monitor quality but the level of involvement is much greater vs a house in a mass development. 


I like quantifiable proof of performance so this appeals to me. What everyone wants is a comfortable house. I hope the availability of simple tests akin to this in the future will help avoid rewarding builders who produce the lowest standards of housing.  



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In effect I did that on my build. For the whole of November I had a single electric convector heater on 24/7. There are no internal doors fitted yet.


Each day I compared internal temperature and external temperature and concluded that the modest 700W of heat was maintaining the house temperature 10 degrees above outside temperature.  You do need to tun this test over a long period as the house responds very slowly to changes in outside temperature.


I did this test as I was doubting the insulation was as effective as it should be, but the test confirmed the heat loss was exactly as predicted using Jeremy's heat loss spreadsheet. So I know I am on track to have a maximum heat input requirement of 2500W when it's +20 inside and -10 outside.


When I complete the new house, I will almost certainly buy an electricity watt hour meter and install that to just measure the power consumed by the ASHP so I will have a real measure of heating power separate from all other electricity usage.


I didn't have any doubt about the type or amount of insulation fitted as I fitted it all myself.

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