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Heat loss calculators and spread sheets
Please can you post your favoured heat loss calculators and spreadsheets in this thread so that we can build up a repository for those homeowners that want to undertake their own calculations?
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I’ve used the freedom spreadsheet for my own place and am halfway through doing the calcs for my builder friend on the same.
I’ve also modelled my place in heatpunk, that’s quite nice, although not as fast as the freedom toolkit.
I have used the stelrad windows program for rad sizing but haven’t looked at their other offerings yet, will do so.
Off grid on the isle of purbeck
2.4kW solar, 15kWh Seplos Mason, Outback power systems 3kW inverter/charger, solid fuel heating with air/air for shoulder months, 10 acres of heathland/woods.
My wife’s house: 1946 3 bed end of terrace in Somerset, ASHP with rads + UFH, triple glazed, retrofit IWI in troublesome rooms, small rear extension.
@hughf, is the Freedom one free to download?
🔥 Britain’s Heat Pump Shitshow
How Installing a Heating System Became a National Nervous Breakdown
Free UK shipping.
Rewritten and updated for 2027
📘 From Zero to Heat Pump Hero
🛠️ Bodge Buster
New to heat pumps?
Take the Heat Pump Fundamentals course and use INTRO50 at checkout for 50% off.
Posted by: @editor@hughf, is the Freedom one free to download?
They were sending copies out to anyone go asked for a while, not sure what the current situation is as they’ve taken down the video instructions from their YouTube channel. I’ve since stuffed it in my GitHub which is probably against various terms of use but I’ll deal with that issue if it ever arises.
Off grid on the isle of purbeck
2.4kW solar, 15kWh Seplos Mason, Outback power systems 3kW inverter/charger, solid fuel heating with air/air for shoulder months, 10 acres of heathland/woods.
My wife’s house: 1946 3 bed end of terrace in Somerset, ASHP with rads + UFH, triple glazed, retrofit IWI in troublesome rooms, small rear extension.
Posted by: @editoris the Freedom one free to download?
It used to be (from the Freedom Heat Pump's website) but you now have to create an account (I wonder why) which I declined to do as it is not clear what that involves or what it gives you access to. The Wayback Machine does not appear to have the actual downloads, though it does have the folders. But all is not lost, a copy of v3.3 (early 2022) is available on this very forum!
Midea 14kW (for now...) ASHP heating both building and DHW
Posted by: @hughfthey’ve taken down the video instructions from their YouTube channel
Looks like the cancel culture has hit Headroom Heatpumps...
Midea 14kW (for now...) ASHP heating both building and DHW
🔥 Britain’s Heat Pump Shitshow
How Installing a Heating System Became a National Nervous Breakdown
Free UK shipping.
Rewritten and updated for 2027
📘 From Zero to Heat Pump Hero
🛠️ Bodge Buster
New to heat pumps?
Take the Heat Pump Fundamentals course and use INTRO50 at checkout for 50% off.
@editor - it was just hiding in plain sight, as things so often are!
People do need to be aware that, while good, Freedom's calculator is not perfect:
(1) famously, it over-estimates Midea heat pump output at lower ambient temps
(2) not all building materials are available, sometimes you have to choose something that is not what you home has, but is 'near enough'
(3) it uses a relatively crude method of calculation radiator output (based on area) which doesn't take into account an actual radiator's output (but most of the time it is 'good enough'). It also lacks the option of using K3 rads (but you can hack it to make it do that, but make sure you get the numbers right)
(4) v3.3 uses/tests for the MCS heat pump must supply 100% or more of the heat demand requirement (if it doesn't you FAIL). I think MCS in their infinite wisdom may have changed that requirement. Perhaps someone more up to date on MCS requirements could comment
Lastly, it needs a LOT of data entry. Typos are easy, check and double check your entries, and do visual sanity checks on your results eg if a large room has a small heat loss, you probably made a typo in a measurement entry somewhere.
Midea 14kW (for now...) ASHP heating both building and DHW
Does anyone else get a "Problem with content in this workbook" error when opening this file in Excel? I am using Excel 2016
@abernyte - I use LibreOffice Calc. Maybe try that?
Midea 14kW (for now...) ASHP heating both building and DHW
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