Heating options

[Quince]

Hello all,

I'm new to this group and wondered if anyone has any experience with electric under floor heating.

We are renovating and extending a two bedroom 1870's farm workers cottage in the middle of nowhere in Lincolnshire. Therefore we are not on the natural gas network and are never likely to be. We have solar panels installed but at present can't benefit from storage batteries and charging during cheaper night tariffs, due to lack of WAN in our area. Our heating at the moment is radiators in most rooms supplied by a gas boiler running on LPG, however the previous owner set it up with 47kg cylinders that cost almost £100 each to replace and if we used this heating as normal people do it would cost around £400 per month! We also have a couple of log burners which we use in the evenings.

In the existing cottage the ceilings are very low, so unless we dig out the floors it would not be practical to install wet UFH. We could use this in the extension but the cost of an air source heat pump prohibits this as we are on a very tight budget and the only other option I can see is installing an LPG tank, however this would be an expensive install and running cost.

We came across a Norwegian electric system that looks like a solution, EP Warmfloor which is supposedly a low-energy, low-voltage, self-regulating underfloor heating system. We would be laying tiled floors which would act as large radiators. This would also get rid of radiators, which would be a benefit as the rooms are not huge. The purchase price of this system is not cheap but nor are the alternatives. I've read that the heating up phase is quite expensive but once temperature is reached it is economical.

We would normally like to keep the thermostat on about 18 deg.C, turning down to 15 over night. We would still use the log burners if we needed a boost. We are in the process of insulating the whole cottage, room by room, using breathable methods.

Has anyone had any experience with EP Warmfloor? or could anyone suggest any alternative ideas.

Thanking you in advance,
Diane

 

[Rosemouse]

I don't know if this will help but friends of mine renovated a very old cottage in Wales and for various reasons couldn't install much in the way of heating system, and eventually came across infra-red heating panels which they say were perfect in smaller spaces and relatively economical. On their recommendation I purchase three of these heating panels, two small and one large, to get us through the worst of the winter in this unrenovated disaster area of a house - i have a wood stove on order but it is two months late. Temperatures have been between 5 and -6 degrees here for the past two months, and I just had our latest electricity bill and it is down about a third on the same time last year when we were only able to use the 1990's electric wall radiators. If this house was properly insulated and the windows and doors weren't creaking drafty wrecks, I suspect that these three heaters would be even more efficient. Anyway for what it's worth this might be a solution in some rooms. But make sure you get a proper infrared heater. In reaearching i found that not all of them are equal, some of them use just as much power as ordinary electric heaters. I got my three from Herschel. They were not cheap but I am pretty pleased with them and will be moving the biggest one over to my work studio as soon as the wood stove is installed.

 

[Quince]

I don't know if this will help but friends of mine renovated a very old cottage in Wales and for various reasons couldn't install much in the way of heating system, and eventually came across infra-red heating panels which they say were perfect in smaller spaces and relatively economical. On their recommendation I purchase three of these heating panels, two small and one large, to get us through the worst of the winter in this unrenovated disaster area of a house - i have a wood stove on order but it is two months late. Temperatures have been between 5 and -6 degrees here for the past two months, and I just had our latest electricity bill and it is down about a third on the same time last year when we were only able to use the 1990's electric wall radiators. If this house was properly insulated and the windows and doors weren't creaking drafty wrecks, I suspect that these three heaters would be even more efficient. Anyway for what it's worth this might be a solution in some rooms. But make sure you get a proper infrared heater. In reaearching i found that not all of them are equal, some of them use just as much power as ordinary electric heaters. I got my three from Herschel. They were not cheap but I am pretty pleased with them and will be moving the biggest one over to my work studio as soon as the wood stove is installed.

Thank you for your reply, it sounds like your house is similar to ours! I will look into the heaters.

 

[Cubist]

How large are the wood-burners you have there? Also, why would you think that a wet CH system is not possible? In addition I'm not sure what you mean by WAN - this term refers to Wide Area Networks communication systems in my understandings - so I'm a little unclear concerning your use in context with your solar panels and batteries?

 

[Flyfisher]

We came across a Norwegian electric system that looks like a solution, EP Warmfloor which is supposedly a low-energy, low-voltage, self-regulating underfloor heating system. We would be laying tiled floors which would act as large radiators. This would also get rid of radiators, which would be a benefit as the rooms are not huge. The purchase price of this system is not cheap but nor are the alternatives. I've read that the heating up phase is quite expensive but once temperature is reached it is economical.

I tend to think of heating systems from the perspective of basic physics. Think of the room as a box of a certain size that will 'leak' heat at a certain rate. To maintain the interior of the room at a given temperature, the heat being lost must be replaced at the same rate by whatever heating system is within the room, whether it's an open fire, a wood stove, a conventional radiator or underfloor heating.

All these heating systems require a source of energy and, of course, different energy sources cost varying amounts, so that's one important variable when thinking about heating costs. Another important variable is the efficiency of getting the fuel energy into the room to be heated. Thus, an open fire will lose a lot of heat up the chimney, which is lost to the room, making it much less than 100% efficient, whereas an in-room electric heater will be 100% efficient in converting the electrical energy into heat.

But being 100% efficient does not mean that electric heating will be cheaper than an open fire because of the price difference for the two energy sources and all know that electrical energy is amongst the highest of all energy sources. It's interesting to compare the energy costs of various sources and there are many online sources of this information.

A couple of interesting things arise from such data. For example, firewood turns out to be more expensive than coal, if you have to buy the firewood, for the amount of energy released. Also, heat pumps are currently in vogue because of their 'high efficiency' and it's certainly true that they can be around 300-350% efficient, meaning that they can convert 1kWh of electricity into 3-3.5kWh of 'heat' ( I say 'heat' because kWh is not really a unit of 'heat', but it's close enough for this discussion). Fine, but 1kWh of electricity will cost around 28p and 1kWh of mains gas will cost about 7p, ie 400% MORE than than electricity, so even allowing for the less-than-100%-efficiency of a condensing gas boiler, a heat pump will be no cheaper to run than a mains gas heating system. Admittedly, mains gas is probably the cheapest form of energy and is not available to everyone, but my point is that it's important to look carefully behind the 'headlines' and be careful when comparing the myriad of heating systems available.

But I digress, so back to electric underfloor heating and the statement "I've read that the heating up phase is quite expensive but once temperature is reached it is economical. ". I have underfloor heating, both wet and electric' and it's true that it takes a while for the floor to heat up compared to, say, a fan heater or conventional radiator, so that could be regarded as 'expensive' in the sense that the room itself won't heat up quickly, but don't forget that when the heating is switched off the floor will remain warm for a fairly long time, so that could be regarded as 'free' heating, which of course it isn't really. In other words, it all balances out in the end and the real cost boils down to how many kWhs are required to warm up the room and, importantly, to keep it warm, which will depend on the rate of heat loss from the room. In that respect, I doubt that electric underfloor heating will be any cheaper to run than electric radiators or fan heaters.

For that reason, I've only fitted electric underfloor heating in a bathroom, which I only heat when we have guests. My other heated floors are 'wet' systems and I'm fortunate to have mains gas, so the energy required to warm the rooms is cheaper than using electricity, and would also be cheaper (I think) using LPG. A 'wet' UFH system is certainly more versatile than an electric one because it can be 'driven' by a wide range of energy sources - basically anything that can generate hot water. It is also well-suited for use with heat pumps because they typically operate at lower temperatures than a 'traditional' central heating system, which is ideal for UFH systems where the entire floor is basically a very large 'radiator'.

 

[Flyfisher]

In addition I'm not sure what you mean by WAN - this term refers to Wide Area Networks communication systems in my understandings - so I'm a little unclear concerning your use in context with your solar panels and batteries?

I think you're right about WAN and I'm guessing the lack of it for the OP means that a smart meter is not possible, which I believe is a prerequisite for getting the best out of solar PV/battery systems.

 

[Flyfisher]

I don't know if this will help but friends of mine renovated a very old cottage in Wales and for various reasons couldn't install much in the way of heating system, and eventually came across infra-red heating panels which they say were perfect in smaller spaces and relatively economical. On their recommendation I purchase three of these heating panels, two small and one large, to get us through the worst of the winter in this unrenovated disaster area of a house - i have a wood stove on order but it is two months late. Temperatures have been between 5 and -6 degrees here for the past two months, and I just had our latest electricity bill and it is down about a third on the same time last year when we were only able to use the 1990's electric wall radiators. If this house was properly insulated and the windows and doors weren't creaking drafty wrecks, I suspect that these three heaters would be even more efficient. Anyway for what it's worth this might be a solution in some rooms. But make sure you get a proper infrared heater. In reaearching i found that not all of them are equal, some of them use just as much power as ordinary electric heaters. I got my three from Herschel. They were not cheap but I am pretty pleased with them and will be moving the biggest one over to my work studio as soon as the wood stove is installed.

I've read about infra-red heaters and my understanding is that they (basically) heat the person rather than the room, so their 'efficiency' and lower running costs come from the fact that the occupants feel warm without having to heat the entire room.

Although I've no direct experience of this sort of heating it does make sense to me because we struggle to get our rooms up to a 'normal' temperature (20-21c ?) and they are typically around 17c, or a bit colder when the outside temperatures are low (don't we just love draughty period properties!). But, we also have multifuel stoves and when lit with the doors open, the radiant heat makes us feel very comfortable even if the air temperature in the room is around 17c. There's also something quite comforting about coming in from the cold and warming up in front of a hot fire rather than just being in a 21c room, so perhaps it's more psychological than physical, I don't know. But in the words of the song, 'if it feels good, do it' !

 

[Cubist]

I think you're right about WAN and I'm guessing the lack of it for the OP means that a smart meter is not possible, which I believe is a prerequisite for getting the best out of solar PV/battery systems.

Having steadfastly resisted all blandishments to install a Smart Meter here and have therefore made no effort to understand how their electronic communications capabilities and requirements are satisfied. Technically I know that the very wires used to provide electrify to the consumers home could be used for this purpose but I know also that they could very easily piggy-back on that consumers domestic wi-fi network powered by their router. That aside, and recognising the part that satellite and wi-fi services have a role on modern WAN services, I'm still puzzled by the OPs reference.

 

[Quince]

How large are the wood-burners you have there? Also, why would you think that a wet CH system is not possible? In addition I'm not sure what you mean by WAN - this term refers to Wide Area Networks communication systems in my understandings - so I'm a little unclear concerning your use in context with your solar panels and batteries?

Hi, we have a 8kw and 12kw, they are perfect for when we sit down in the evenings but also not cheap to run.

The downside of a wet system is that it would have to run off LPG, which is expensive to install the tank and ongoing with running costs, I don't qualify for any grants for heat pumps and the pay back period would take the rest of my life! I would like to get away from normal radiators as they take up valuable wall space in a small cottage and our ceilings are too low to raise the floors.

Yes it is Wide Area Network, In my understanding you can't utilise the cheaper rate electricity at off peak times to charge the batteries unless you have a smart meter and that needs a WAN to work properly. We still have a dial meter

 

[Flyfisher]

Having steadfastly resisted all blandishments to install a Smart Meter here and have therefore made no effort to understand how their electronic communications capabilities and requirements are satisfied. Technically I know that the very wires used to provide electrify to the consumers home could be used for this purpose but I know also that they could very easily piggy-back on that consumers domestic wi-fi network powered by their router. That aside, and recognising the part that satellite and wi-fi services have a role on modern WAN services, I'm still puzzled by the OPs reference.

I've never quite understood the apparently widespread resistance to smart meters, but that's probably another topic.

They basically communicate over a virtual, encrypted, WAN that is piggy-backed onto existing cellular and radio networks. They don't use the power lines or domestic wifi and are completely independent of anything else in the house, but they do enable the many 'smart' tariffs that are now becoming available, which in my case means I now pay about 10p per kWh on average for my electricity instead of the peak rate of around 28p.

How do smart meters send readings?

Millions of smart meters are now connected to the DCC’s secure network, bringing consumers and energy suppliers closer to their data. But how do smart meters work? How do they send readings? Who can access the data?

www.smartdcc.co.uk

 

[fernicarry]

UFH needs an effective layer of insulation under it otherwise half of the heat radiates downwards into the sub floor. Doesn't matter whether its wet or dry, fast or slow.

Maybe a pellet boiler would be an option for wet heating. I have no idea how the running costs compare to bottled gas however.

Agree the economics on HP's are dreadful but eventually it will be the only option available. I think the presumption of our glorious leaders is that we'll all have HP's running at COP of 4 or more so they don't need to bother with sorting out the broken wholesale electricity market.

 

[Flyfisher]

The downside of a wet system is that it would have to run off LPG, which is expensive to install the tank and ongoing with running costs, I don't qualify for any grants for heat pumps and the pay back period would take the rest of my life! I would like to get away from normal radiators as they take up valuable wall space in a small cottage and our ceilings are too low to raise the floors.

I don't know about the installtion costs for an LPG tank but the actual energy cost of LPG is a lot less than electricity. A quick search returned this:

The price of LPG per kilowatt hour (kWh) in the UK can vary depending on location, annual consumption, and the type of LPG used. For example, in October 2022, bulk LPG cost 45 pence per liter, or 6.35 pence per kWh, while a 47 kg gas cylinder cost 9.32 pence per kWh.

A bit out of date but still shows that LPG is considerably cheaper than electricity for the same heat output, which is the thing that really matters whether it's 'wet' or electric underfloor heating.

 

[Quince]

I tend to think of heating systems from the perspective of basic physics. Think of the room as a box of a certain size that will 'leak' heat at a certain rate. To maintain the interior of the room at a given temperature, the heat being lost must be replaced at the same rate by whatever heating system is within the room, whether it's an open fire, a wood stove, a conventional radiator or underfloor heating.

All these heating systems require a source of energy and, of course, different energy sources cost varying amounts, so that's one important variable when thinking about heating costs. Another important variable is the efficiency of getting the fuel energy into the room to be heated. Thus, an open fire will lose a lot of heat up the chimney, which is lost to the room, making it much less than 100% efficient, whereas an in-room electric heater will be 100% efficient in converting the electrical energy into heat.

But being 100% efficient does not mean that electric heating will be cheaper than an open fire because of the price difference for the two energy sources and all know that electrical energy is amongst the highest of all energy sources. It's interesting to compare the energy costs of various sources and there are many online sources of this information.

A couple of interesting things arise from such data. For example, firewood turns out to be more expensive than coal, if you have to buy the firewood, for the amount of energy released. Also, heat pumps are currently in vogue because of their 'high efficiency' and it's certainly true that they can be around 300-350% efficient, meaning that they can convert 1kWh of electricity into 3-3.5kWh of 'heat' ( I say 'heat' because kWh is not really a unit of 'heat', but it's close enough for this discussion). Fine, but 1kWh of electricity will cost around 28p and 1kWh of mains gas will cost about 7p, ie 400% MORE than than electricity, so even allowing for the less-than-100%-efficiency of a condensing gas boiler, a heat pump will be no cheaper to run than a mains gas heating system. Admittedly, mains gas is probably the cheapest form of energy and is not available to everyone, but my point is that it's important to look carefully behind the 'headlines' and be careful when comparing the myriad of heating systems available.

But I digress, so back to electric underfloor heating and the statement "I've read that the heating up phase is quite expensive but once temperature is reached it is economical. ". I have underfloor heating, both wet and electric' and it's true that it takes a while for the floor to heat up compared to, say, a fan heater or conventional radiator, so that could be regarded as 'expensive' in the sense that the room itself won't heat up quickly, but don't forget that when the heating is switched off the floor will remain warm for a fairly long time, so that could be regarded as 'free' heating, which of course it isn't really. In other words, it all balances out in the end and the real cost boils down to how many kWhs are required to warm up the room and, importantly, to keep it warm, which will depend on the rate of heat loss from the room. In that respect, I doubt that electric underfloor heating will be any cheaper to run than electric radiators or fan heaters.

For that reason, I've only fitted electric underfloor heating in a bathroom, which I only heat when we have guests. My other heated floors are 'wet' systems and I'm fortunate to have mains gas, so the energy required to warm the rooms is cheaper than using electricity, and would also be cheaper (I think) using LPG. A 'wet' UFH system is certainly more versatile than an electric one because it can be 'driven' by a wide range of energy sources - basically anything that can generate hot water. It is also well-suited for use with heat pumps because they typically operate at lower temperatures than a 'traditional' central heating system, which is ideal for UFH systems where the entire floor is basically a very large 'radiator'.

Thank you for your very thorough reply

I have looked at all types of energy source and when you also consider the cost of installing heat pumps and LPG tanks etc. plus the ongoing cost of servicing boilers, it would take the rest of my life to reach payback. Anything would be better than LPG in 47kg cylinders!

We love the log burners but would also love some background heat when they are not lit. I also love the idea of UFH and having toastie feet. The EP Warmfloor system that I have looked at is all individually, thermostatically controlled and is said to only pull power where needed (there is a technical name for this, something to do with resistance) so if there is solar gain from a window or patio doors for instance no power goes to that area of the floor. I just wonder if it actually works like that.

 

[Quince]

UFH needs an effective layer of insulation under it otherwise half of the heat radiates downwards into the sub floor. Doesn't matter whether its wet or dry, fast or slow.

Maybe a pellet boiler would be an option for wet heating. I have no idea how the running costs compare to bottled gas however.

Agree the economics on HP's are dreadful but eventually it will be the only option available. I think the presumption of our glorious leaders is that we'll all have HP's running at COP of 4 or more so they don't need to bother with sorting out the broken wholesale electricity market.

I will look into a pellet boiler, thank you

 

[Cubist]

Here we have a similar 8kw and a larger 14kw wood-burners which are used for almost all of our heating needs - the only exception being a small fan heater for occasional/emeregency use. The larger of the two also drives our wet CH system and as such shoulders most of the heating burden of the house which is a four bedroom thatched oak timber frame cottage and attached barn conversion. Your 12kw stove should be capable of a very similar performance and perhaps with no modifications. Also, it may, if its a relatively modern product, still be capable of having a hot water jacket installed which can be used to drive a wet ch system. Or, as another option you might consider replacing the extant stove with a more modern product that includes a ch water jacket. Your use practices will play a large part in how efficiently the wood-burners work for you and long, and sometimes bitterly won, experience is needed to get the best from them - if you're willing to share those practices here there are a few members here who may be able to offer some advice.

Sadly you may have been caught in the original Smart Meter scam. If the house currently has an old dial type Economy 7 meter alongside the standard one you should still be able to enjoy the E7 tariffs. If not then you will be obliged to get a Smart Meter before you can do so. The SM simply controls the billing rate for what you use and when you use it. As @Flyfisher has just explained for my benefit the SM connects to Cell Phone and Radio networks for its WAN connections - there is nothing internal to your home needed for it to do this.

 

[Flyfisher]

UFH needs an effective layer of insulation under it otherwise half of the heat radiates downwards into the sub floor. Doesn't matter whether its wet or dry, fast or slow.

Maybe a pellet boiler would be an option for wet heating. I have no idea how the running costs compare to bottled gas however.

Agree the economics on HP's are dreadful but eventually it will be the only option available. I think the presumption of our glorious leaders is that we'll all have HP's running at COP of 4 or more so they don't need to bother with sorting out the broken wholesale electricity market.

Yes, good insulation under the heated floor slab is essential for an efficient UFH system, whatever the energy source.

Regarding wood pellet boilers, when I looked at this option about 15 years ago it seemsed that it only got close to being a sensible option if you have enough space to store many tons of pellets, ie 10-20 tons, because of the delivery costs. Things may have changed now, I don't really know because I gave up looking at all the alternatives when I discovered I could connect to mains gas for £300. This may not be a 'forever' option (what is?) but it has remained the cheapest wat to buy energy over the past 15 years or so and I would wager a reasonable sum that it will remain so for my remaining years.

I agree that our glorious leaders seem to imagine a world entirely powered by electricity as if this will somehow magically reduce our current dependence on fossil fuels. Perhaps in time it might, but we should remember that electricity is not a SOURCE of energy, only a means of moving it about. Same with hydrogen actually, but that's another digression.

 

[Cubist]

They basically communicate over a virtual, encrypted, WAN that is piggy-backed onto existing cellular and radio networks.

Ah, then that may explain the reluctance of the provider organisations - Cell Phone and Radio signals around here are notoriously poor.

 

[Cubist]

I've never quite understood the apparently widespread resistance to smart meters, but that's probably another topic.

Simple really... I hate being nagged. the First Lady doesn't do it, honest, but I'm perpetually surrounded by electronic devices telling me I'm 2mph above the limit and the service is overdue, or telling me its someones birthday or the tax man wants another contribution or an insurance premium needs to be paid in 3 months time or........

I am a grown up and perfectly capable of organising my own life thanks all the same and these electronic prompts and helpful reminders and interventions have done more than anything else to make me a grumpy old curmudgeon.

Cheers,
Luddite of Ludlow

 

[Quince]

Here we have a similar 8kw and a larger 14kw wood-burners which are used for almost all of our heating needs - the only exception being a small fan heater for occasional/emeregency use. The larger of the two also drives our wet CH system and as such shoulders most of the heating burden of the house which is a four bedroom thatched oak timber frame cottage and attached barn conversion. Your 12kw stove should be capable of a very similar performance and perhaps with no modifications. Also, it may, if its a relatively modern product, still be capable of having a hot water jacket installed which can be used to drive a wet ch system. Or, as another option you might consider replacing the extant stove with a more modern product that includes a ch water jacket. Your use practices will play a large part in how efficiently the wood-burners work for you and long, and sometimes bitterly won, experience is needed to get the best from them - if you're willing to share those practices here there are a few members here who may be able to offer some advice.

Sadly you may have been caught in the original Smart Meter scam. If the house currently has an old dial type Economy 7 meter alongside the standard one you should still be able to enjoy the E7 tariffs. If not then you will be obliged to get a Smart Meter before you can do so. The SM simply controls the billing rate for what you use and when you use it. As @Flyfisher has just explained for my benefit the SM connects to Cell Phone and Radio networks for its WAN connections - there is nothing internal to your home needed for it to do this.

Fortunately we don't have a SM at all and unfortunately I think our meter even pre-dates economy 7 ability.

At the moment the LPG boiler is handling our hot water requirements and CH, we use the radiators for a couple of hours in the morning and then the multi-fuel burners get lit in the evening and if we have a rare afternoon free of renovating jobs at the weekends.

 

[fernicarry]

all individually, thermostatically controlled and is said to only pull power where needed (there is a technical name for this, something to do with resistance) so if there is solar gain from a window or patio doors for instance no power goes to that area of the floor

Sounds like some sort of PTC thing. Positive thermal coefficient. The hotter it gets the higher the resistance becomes so less current flows and less power is developed. The electric heater in my car apparently does this. For that to work in a localised fashion as described you'd need many heating elements in parallel. Haven't googled the product to see if that's how it actually works. It does seem rather like overkill to be finely managing the power output at that level when most of us get by with a room stat acting as a crude on-off switch.

None of that magically changes the laws of thermodynamics that controls how the heat radiates and conducts away from the floor. If there is less thermal resistance down the way then that's where the heat will go.