Notifications

Clear all

Finding out the heat loss and U-value of your house ?

Page 1 / 3 Next

Air Source Heat Pumps (ASHPs)

Last Post by Chris-in-Kemnay 5 years ago

25 Posts

7 Users

42 Reactions

5,981 Views

RSS

Bob@Lochinver

(@boblochinver)

Reputable Member Member

Joined: 5 years ago

Posts: 109

Topic starter 07/03/2021 12:56 pm

One Item that I see a lot and would like to understand more is how best to obtain the proper heat loss and u-value of my house. I know there are calculators out there that will help with this but i am often confused by the more technical terminology used for different types of existing insulation and not all online systems will allow for you to put down exactly what you have in your individual house. It would also be nice to work out what it could be after any renovation work has been done such as doing Internal wall insulation and replacing windows with new triple glazing and new improved doors etc. Does anyone know if there are companies out there that will take your existing plans of a building and break it down for each individual room and what it would need for heating to keep it at the normal 20 / 21 heat level ?

👍

Quote

Kev M

(@kev-m)

Famed Member Member

Joined: 5 years ago

Posts: 1276

07/03/2021 3:46 pm

Bob, I believe you can ask a reputable ASHP installer to do a full MCS survey without signing up for anything and I've seen figures of £200 quoted for this. Alternatively, as you say there are calculators but some are either very simplistic or seem to require detailed knowledge of building materials. You can use the MCS spreadsheet yourself but it's not very user friendly. I found the Stelrad calculator good; if you go to Stelrad.com, say you're a professional and set up an account, you can model every room in your house. You need some knowledge of your house's construction but a lot of it is done via drop downs and is quite intuitive. You can vary temps in each room and model the flow temps typical of a heat pump. Since it's aimed at flogging radiators, it will size these as well as the boiler size needed.

👍

ReplyQuote

Bob@Lochinver

(@boblochinver)

Reputable Member Member

Joined: 5 years ago

Posts: 109

Topic starter 07/03/2021 3:59 pm

@kev-m thanks for info and I'll take a look at the site, I guess I dont mind paying something for someone to give me a proper honest figure of what my home would need to heat it, I worry that as the people that would give me the figures from an air source point of view could potentially make it work with the systems they are pushing which might not always be the most efficient.

👍

ReplyQuote

Chris-in-Kemnay

(@chris-in-kemnay)

Estimable Member Member

Joined: 5 years ago

Posts: 52

07/03/2021 6:31 pm

@boblochinver I'd love to share the Excel calculator and photos but i can't find a way of doing do on the forum. You can PM me if you'd like.

Chris

👍

ReplyQuote

Mars

(@editor)

Illustrious Member Admin

Joined: 5 years ago

Posts: 3593

07/03/2021 6:44 pm

@chris-in-kemnay we've disabled the ability to upload .xls file as a security precaution. We've also lowered the amount of posts required to post images. Please try again. There should be an attachment link at the bottom of the reply box.

To prevent spam, posting of links is only allowed when users have made 10 or more posts on the forums.

Get a copy of The Ultimate Guide to Heat Pumps

Subscribe and follow our Homeowners’ Q&A heat pump podcast

👍

ReplyQuote

Chris-in-Kemnay

(@chris-in-kemnay)

Estimable Member Member

Joined: 5 years ago

Posts: 52

07/03/2021 7:12 pm

@editor thats understandable Mars. I see the link and I'll try again when I'm back on the pc.

Thanks

👍

ReplyQuote

Mars

(@editor)

Illustrious Member Admin

Joined: 5 years ago

Posts: 3593

07/03/2021 10:27 pm

@boblochinver we've just had our heat-loss re-calculated last week by the manufacturers using a new and revised "formula", which I'm hoping to receive this week. I had a look at the MCS document two weeks ago, and it's a bit complicated, but there are a lot of keys and legends, and I don't think it'll be too difficult to work out. To speed things, you'll need one of those laser measures to get room measurements (and rad sizes) in a hurry.

If you have the money, any objective calculation will naturally lead to an unbiased result.

If you're up for a challenge, I've attached the MCS heat pump calculation spreadsheet below.

MCS-Heat-Pump-Calculator.zip

Get a copy of The Ultimate Guide to Heat Pumps

Subscribe and follow our Homeowners’ Q&A heat pump podcast

👍

ReplyQuote

Bob@Lochinver

(@boblochinver)

Reputable Member Member

Joined: 5 years ago

Posts: 109

Topic starter 07/03/2021 10:56 pm

@editor Initial view of it is that I still dont know how best to allow for all my external wall having a complete insulation installed on all the external wall facings but internally eg ill take up to 75cm of space along the entire inside of the house walls.

ReplyQuote

Kev M

(@kev-m)

Famed Member Member

Joined: 5 years ago

Posts: 1276

08/03/2021 9:42 am

removed link

I also found this. It lets you build up layers of different materias.

A suggestion to @editor Mars - maybe we could have a sticky with useful links and resources?

www dot vesma dot com/tutorial/uvalue01/uvalue01 dot htm

This post was modified 5 years ago by Kev M

ReplyQuote

Duncan Mac

(@duncan-mac)

Trusted Member Contributor

Joined: 5 years ago

Posts: 33

08/03/2021 4:38 pm

Thanks for the invite to join folks. Interesting and complicated subject. I tried to post something yesterday but I'm not familiar with the Technology so here we go again.

I agree with what everyone is saying and I found that a spreadsheet is downloadable form the MCS (Microgeneration Certification Scheme) website which allows you to design ( or check your installer's design) of each room so that it complies with MCS standards.

The spreadsheet looks at a variety of builds, wall construction, floor makeup and ceiling insulation. It also differentiates room temperatures and external and internal walls. It goes on to compare radiators capacity with requirements and test the capacity of the ASHP which you are considering.

I have used it to question my installers recommendations.

I did notice that your videos on Heat pumps you were advised that you did not need to upgrade your radiators but I think this maybe because of your mix of heating. I don't think its true for every install.

PS very happy to discuss the ROI of my Battery Storage. Its only been in since November but by timeshifting my Grid draw I have reduced cost I believe.

ReplyQuote

Mars

(@editor)

Illustrious Member Admin

Joined: 5 years ago

Posts: 3593

08/03/2021 6:31 pm

Good idea @kev-m - I'll create a sticky along those lines.

Get a copy of The Ultimate Guide to Heat Pumps

Subscribe and follow our Homeowners’ Q&A heat pump podcast

ReplyQuote

Bob@Lochinver

(@boblochinver)

Reputable Member Member

Joined: 5 years ago

Posts: 109

Topic starter 08/03/2021 10:08 pm

Posted by: @duncan-mac

PS very happy to discuss the ROI of my Battery Storage. Its only been in since November but by timeshifting my Grid draw I have reduced cost I believe.

Would be great to see the benefit that you are seeing on the Battery storage.

ReplyQuote