Anyone live in a property with a heat pump and underfloor heating only?

Wishywashy74

Viewed a nice modern build today, has a really high energy efficiency rating, it runs a electric heat pump which heats the upper and lower underfloor heating and has a wood burner as well.

My question is are these's a reliable unit and especially in the winter how do you find it works?

FFHillbilly

is the wood burner tied into the heating system? if so then thats a good backup.
historically reliability of heat pumps hasn't been great and if they do break then getting someone to fix them is even harder, but the newer ones are much better so you probably won't have to worry about it for 10 years.
new "heat pump apprenticeships" are starting this year too which should help solve the lack of skilled labour to maintain them

Wishywashy74

FFHillbilly said:

is the wood burner tied into the heating system? if so then thats a good backup.
historically reliability of heat pumps hasn't been great and if they do break then getting someone to fix them is even harder, but the newer ones are much better so you probably won't have to worry about it for 10 years.
new "heat pump apprenticeships" are starting this year too which should help solve the lack of skilled labour to maintain them

Not sure, I'll have to check with the estate agent tomorrow about that, the place is only 2 years old now so was sort of hoping the newer setups are proven and reliable, especially in the winter.

tacpot12

Ask the estate agent to confirm the make and model of the Heat Pump. This will allow you to research the temperature that the manufacturer says it will work down to. This will depend on the refrigerant, and should be at least -7C and might be as low as -25C. 

Whether this is sufficient depends on where the property is located. A rural property in Scotland is going to need the heat pump to operate at a much lower temperture than a property located in close to the centre of a city in the south of England.

Check Seasonal Coefficient of Performance (SCOP) at the lowest outdoor temperature you can see in any datasheet for the heat pump, and call the manufacturer to find out the SCOP if you think the property is going to experience temperatures much lower than this.  

Underfloor heating is the most efficient way to use the heat from a heat pump, and so with a modern heat pump, it should have no problems heating the home, but this does depend on whether the heat losses from the home have been correctly understood and whether the heat pump has been sized and installed correctly.

The wood burner is a useful backup, but I doubt it is connected to the underfloor heating. Howeverr, if you haven't had a wood burning stove before you might be surprised at how much wood they consume, and how much space the wood takes up if you are going to keep it dry. If you burn damp wood in the stove it will cause expensive problems.

I would also ask the estate agent for the current owners electricity usage data between Summer 2022 and now. This will give you an idea of whether the heat pump is efficient or not. If I had any concerns about the efficiency, I would call an expert in to check the design and installation. It might seem overkill, but you don't want to buy a property where any problems can't be fixed cheaply.  

ThisIsWeird

They aren't new technology - there was one fitted to an extension in our house when we moved in over 20 years ago - and yours should, in theory, be ideally matched to the UFH in a highly insulated new home. It therefore should work superbly, and hopefully be similar in cost to gas to run.

How reliable the units are, I don't know. I'd have thought that some evidence should be coming out by now, since they have been fitted to many new homes now. 

Personally, I'd welcome it as probably the most desirable form of heating and energy supply. Comfortable heat, no visible radiators, 'clean' energy supply. 

Since they are becoming a major new method of heating homes, I'd have thought there would be more and more qualified service agents out there, so hopefully any faults shouldn't take too long to fix. And you do have a backup, whether integrated or not - you shouldn't freeze. Not many properties have such a back up! And, worst case, you plug in an electric heater.

(I wonder - would a wood burner be part of a system that needs electricity to run? What do you do in the event of a power cut?)

Wishywashy74

ThisIsWeird said:

They aren't new technology - there was one fitted to an extension in our house when we moved in over 20 years ago - and yours should, in theory, be ideally matched to the UFH in a highly insulated new home. It therefore should work superbly, and hopefully be similar in cost to gas to run.

How reliable the units are, I don't know. I'd have thought that some evidence should be coming out by now, since they have been fitted to many new homes now. 

Personally, I'd welcome it as probably the most desirable form of heating and energy supply. Comfortable heat, no visible radiators, 'clean' energy supply. 

Since they are becoming a major new method of heating homes, I'd have thought there would be more and more qualified service agents out there, so hopefully any faults shouldn't take too long to fix. And you do have a backup, whether integrated or not - you shouldn't freeze. Not many properties have such a back up! And, worst case, you plug in an electric heater.

(I wonder - would a wood burner be part of a system that needs electricity to run? What do you do in the event of a power cut?)

I was thinking exactly that, with last winter all we heard about was possible power cuts, not ideal if you only have the heat pump to use, fortunately this one has the wood burner in the front room, but food for thought.

I'll also get the make and model of the heat pump and do some research, fortunately we are north east and don't usually see extreme cold spells but better to read into it.

On a plus side I've never seen a energy efficiency chart as high as this one has when viewing a house tbf, currently at 83% but potential to go to 90%.

FreeBear

tacpot12 said: The wood burner is a useful backup, but I doubt it is connected to the underfloor heating. Howeverr, if you haven't had a wood burning stove before you might be surprised at how much wood they consume, and how much space the wood takes up if you are going to keep it dry. If you burn damp wood in the stove it will cause expensive problems.

I have a smallish stove here (nominal 7KW output). My wood store is stacked to the roof with approximately 8 cubic metres of logs wich is just about enough for a really cold winter. Even although we had an extended cold period at the beginning of the year, it was a relatively mild winter, and I still had ~1.5m³ left.

Stacked under cover, there is an additional 10-12m³ of logs being seasoned for winter 2024/5 and 2025/6 - Next spring, I will be looking to source yet more logs to cut, split, and stack.

It is not just the space needed to store a reasonable quantity of fuel. You also need to consider the cost. A 1.6m³ crate of kiln dried oak could set you back £400* and might only last you a month. Purchasing loose loads could be cheaper - Depending on where you are in the country, anywhere between £150 and £300 per load. Once stacked though, you may well be disappointed with just how many logs you get for your money... Wood burning stoves work best if you have access to free/cheap logs, have the space to store a couple years worth, and am prepared to cut, split, and stack. If you are not willing to put in the work, they are just an expensive life style accessory.

Oh, and don't forget the mess... Each time you bring logs in from outside, you'll be rehoming spiders and small bugs. There will be little bits of bark littering the floor around the stove. And each time you clean out the ash, dust will get everywhere. Then as attitudes change, you will become a pariah for your PM2.5 emissions out of the flue. 

* https://www.logsforsale.co.uk/product/2m3-crate

ThisIsWeird

If it breaks down in winter, call out the repair fellow, and either light up the loggie, or plug in an oil-filled rad. It's what we'd all have to do, but in your house it'll be cheaper :-(

chris_n

Most new builds around where I live ( halfway up an Alp in Austria) are heated with underfloor heating and heat pumps. It is significantly colder here in winter than UK and they work fine. However the standards of insulation fitted are generally way higher than UK.