Have booked the Heatgeeks design consultation for next month. The outputs for this look like they’re worth the £250 even if I decide to defer doing the project.
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Be interesting to see if they mention a thermal store for your hot water.
Before I fell off those bastard ladders we had replaced an unvented with one on a heat pump system.
Worked well.
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My ill-educated thoughts are centred around this, Stu
Specifically the Mini Store FAT. As we’ll have problems accommodating a full size cylinder without (more) major expense. There are only two of us in the house and one shower+bath.
Have you looked at a Sunamp or anything like that? You obviously wouldn’t get a heat pump multiplier for energy input but you can then charge in cheap rate or do solar diversion.
Ours is a 10.5kW capacity and we use about 4kWh per day, it looks like it is a similar physical size to the cylinders.
Just did a quick review..
Heatpump
Annually we use ~2790kWh for heating and hot water.
We have a more even temperature throughout the house 21-22°C 24/7 and that also includes the annex room 24/7.
Gas
Annually ~12000kWh averaged over 5 years.
We did not heat the annex room unless using it.
The on off nature of the gas was harder to get a nice even temperature throughout the day.
We also had 3 circulation pumps churning with the gas system, now there’s one.
Hot water availability / use the same.
That’s a 4.3 times greater kWh usage for gas.
SCOP was 4.3. It’s still climbing slowly as I trim the system.
For any other country that didn’t subsidise gas like the UK does, heatpumps would be a complete no brainer. Even a COP of 2 is valued in the Nordic countries!
Thanks to trump’s war gas is no longer as cheap as it was, so the tables are turning…
Already this winter!
Whatever you do, don’t leave the settings as a major installer would leave them thinking they know best.. question everything and test things out.
Every bespoke install is different.
We’d have been lucky to get a SCOP of 3!
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Looks like that is what it is. Modified to be extremely efficient.
They really seem to be on top of their game.
The fact it’s being manufactured up the road is quite appealing too.
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heat geeks said no, too leaky and large seems to be the problem
Have registered for when they expand their range
Thing that confuses me is why won’t the design a system that will improve downstairs only, then it’s normal house sized and that’s where we need the jest in winter, happy with cold bedrooms
If you are going for the MCS boiler replacement grant, they have to conform to certain rules.
The grant is not really for you, it’s for the property in the short and long run.
Something that’s fine for you, might not be okay for the next owner etc.
If you don’t need the grant, I’m sure they’d do anything given enough money.
The leaving water temp of a heatpump is lower than gas etc boiler. 40°C or less verses 75+°C. Homes were built that that high water temp in mind.
So leaky means the cooler rads no matter how large won’t heat it adequately.
Go double or triple glazing, insulate the walls and ceilings, seal it up, get a decent heat retention state and then no problem.
You’ll need dehumidifiers or air circulation probably too..
I have mived in that direction, as we rennovate rooms we are insulating the external walls and adding double or triple glazing
loft and 1st floor insulation between joists too in a bid to get some of the ground floor rooms warmer and it’s starting to make a difference but some of the rooms can’t be reglazed so plan on leaving them empty in the depth of winter
My thinking was a heat pump to focus on the two downstairs rooms we can’t fully insulate would make them less cold but looks like that isn’t the case so need to start foraging for wood and fit a log burner I guess
Can you go secondary glazing - can be quite tasteful, even some stately homes etc have it.
When they do the calculations they are super pessimistic.
Ours was something like 50°C at -3.
Our leaving water plot is actually like this..
Never went above 33°C all winter.
You can zone and have higher water temps in a zone or two but efficiency takes a hit when you zone, I’ve read.
How much gas would you estimate to use in a season in kWh if you heated the place to comfort levels everywhere?
Typically you’d divide that by 3-4 or so and you’d be close to your heatpump size requirement.
We would need around a 3-4kWh one.
They insisted in fitting a 8kWh one!
Fortunately it can modulate down the same as the 4kWh version!
They are super conservative. Don’t want bad press that heatpumps don’t cut it / leave you cold.
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Tbh Steve we have never heated to comfort except on high days and holidays
I recall for Christmas we were burning £50 a day at one point but that was when prices were higher
We tend to use the log burner in lounge and electric heaters to take the chill off the kitchen
pip the heating on for a couple of hours a day when it’s cold but rarely leave it on
we get very hot and bothered when we visit anyone normal and they have heating on 
Secondary is part of the plan yep, not loving the lightweight stuff tho so making our own from pine, acrylic and cupboard magnets so can remove too cleaning and spring to store over summer
lots of small things seem to help so getting better every year.
Not sure I will get to point where modern houses get tho
Yeah that’s the problem, the MCS have their rigid temperature / heat loss guidelines, once the property is heat loss assessed that’s it.
If we ran ours as the installers left it - 50°C water temp at -3°c outside temp we’d be ~25°C indoors and be bouncing on and off the room thermostat like gas.
Very inefficient for a heat pump.
Fortunately you can disable the room stat and go Leaving Water temperature Control and change all the variables on the graph.
I expect you could be okay with a smart heatpump install at your expectation levels but not MCS grant parameters and you’d have to convince the installers you would be happy with it.
Some seem to have 18°C room temps - even living room!
If we could handle that our SCOP would be much higher. Approaching 5 maybe..
Having lived in Sweden (warm in, cold out) we couldn’t hack 18°c. Some can apparently.
Forgot to say: have you had a look at
The chat forum there is super helpful.
You’ll get help and answers and there are all sorts of installs, thick stone walls, older properties etc there.
Thanks Steve will take a look
My survey is set for 1st week in October. I’ll spin up a new thread with all the results and quotes after it’s done.
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We run a daytime minimum of 17º and them bump to 19º overnight to use the cheap rate. The rest is what valve amps are for…
17 balmy
You can have ufh with carpets. We’ve got ufh throughout upstairs, with Westex wool carpets.