measuring heat loss and/or air changes

[Kaymo]

Hi,

Quick background is that I have an old house in the country, central Scotland, a little elevated and exposed to wind and I am trying to improve the insulation and air tightness etc. I have already done some things like the obvious loft and under raised floor insulation etc and blocked the worst of the drafts in most rooms but I find that afterwards that the improvement is a little subjective and I would like to find a way to benchmark before I start a room to see how much this is improved and also to see how much more improvement could be made.

I understand that drafts or number of air changes could be one of the biggest factors but is there any cheap/DIY method of measuring this. (I suspect as this probably involves using a test gas and meter or pressure testing that the answer will be no.)

Or, as ultimately the aim is to reduce the heat loss I wondered if it might be to measure this somehow? I had thought of possibly heating the room to a reasonably high temperature (in relation to outside temp), turning the heating off then measuring the decay over a period of time.

Does anyone have any experience of this or think there is any value in doing this? I have a very cold north facing room that I havent done anything to yet thought it might be useful to find out just how bad the heat retention is before I start.

 

[Geps]

You could hire a thermal imaging IR thermometer....it'll give you a guide as to how much heat is being lost but much more useful is also where.

 

[Kaymo]

Thanks Geps, I had thought of this and I have used a simple IR thermometer in the past to similar effect but the house is very thick sandstone walls and internal lathe and plaster. I am fairly convinced that there are drafts behind the plaster which would be carrying the heat loss away before it got through the walls. I was thinking more of a way to benchmark the current situation prior to investigating where the heat is going.

 

[^woody^]

No offence, but a bit of a pointless exercise

All you will find out is how quick a room gets cold. You wont know how or why or via which route or what improvements may help

You probably want a SAP calculation based on the materials currently there, and then you can see how an element could be improved

 

[Geps]

Thanks Geps, I had thought of this and I have used a simple IR thermometer in the past to similar effect but the house is very thick sandstone walls and internal lathe and plaster. I am fairly convinced that there are drafts behind the plaster which would be carrying the heat loss away before it got through the walls. I was thinking more of a way to benchmark the current situation prior to investigating where the heat is going.

It'll give accurate surface temperatures allowing you to set the bar for whatever improvements you want.

 

[Kaymo]

Woody,
I don't see how its a pointless exercise. The analogy is, If I want to do try and improve the MPG of my car, the first thing I would do is monitor this to find out what the current MPG is, then I have a baseline to work from. If my car was getting 45mpg, and the ideal for the model was 50mpg I wouldn't worry too much about it but if I was getting 25mpg I might change some components then check what improvement that made.

Perhaps I am not explaining myself well but if was to find that a modern, well insulated room of the same size, aspect etc took 1kW to heat, but my room takes 3kW to heat then there is obvious room for improvement. If I then insulate under the floor and it now only needs 2kW to heat then I can evaluate the impact.

What I am wondering is if anyone else has experience of doing this. Maybe it would be better to do it the other way around, using an electric heater to raise the temperature of the room and measuring the kw per hour required?

Thanks.

 

[^woody^]

The analogy does not work for me. It's not a pointless exercise to try and improve insulation, but in the way you are thinking of going about it.

It will need to be done via SAP calculations

 

[Kaymo]

I am surprised at this way of thinking, how do you know if you have improved anything if you don't measure it before you start?