Explain it like I am five
October 16, 2023 6:32 AM Subscribe
We have been completely defeated by British heating.
Hello,
We recently moved to a house in London, UK and we're a bit mystified by our heating system, as the systems in our home countries are very different. Please explain British heating systems to me as though I am five, hopefully leading to (1) a warmer house, and (2) lower bills!
The heating system:
- Gas boiler plus radiators. The radiators have dials at the bottom allowing them to be cranked up or down. The gas boiler does the hot water but also seems to be controlled by a portable, programmable thermostat.
- electric, underfloor heating in some of the rooms.
Last winter we were underwater with a new baby and mostly used the underfloor heating, leading to some truly insane electricity bills. This year we have figured out that gas is cheaper than electricity, so want to use our radiators more ... but I think we're doing it wrong?
The issue is that the thermostat can only be in one room at a time. So if its in the living room and that room reaches the target temperature, it shuts off for the whole house. There are different levels of insulation across our house, so its difficult to find the one perfect place to put it. Plus we use the living room a lot during the day, and then not at all until morning.
I saw a video from the Energy Savings Trust that says to put the thermostat in the hallway. We don't usually heat ours, so if we did that our heating system would run all the time (unless programmed to be off). That sounds expensive, unless the cost can be mostly controlled with the radiator dials?
Is the answer to have the heating system always "on" during key times of day, and install smart radiator valves so the different rooms are kept at the right temperature despite their different uses and levels of insulation?
Oh, and should we be using our underfloor heating at all? What would be the point of installing two different heating systems?
Apologies for rambling. This is 100% the kind of thing I would normally ask my dad, but he doesn't live in the UK!
Hello,
We recently moved to a house in London, UK and we're a bit mystified by our heating system, as the systems in our home countries are very different. Please explain British heating systems to me as though I am five, hopefully leading to (1) a warmer house, and (2) lower bills!
The heating system:
- Gas boiler plus radiators. The radiators have dials at the bottom allowing them to be cranked up or down. The gas boiler does the hot water but also seems to be controlled by a portable, programmable thermostat.
- electric, underfloor heating in some of the rooms.
Last winter we were underwater with a new baby and mostly used the underfloor heating, leading to some truly insane electricity bills. This year we have figured out that gas is cheaper than electricity, so want to use our radiators more ... but I think we're doing it wrong?
The issue is that the thermostat can only be in one room at a time. So if its in the living room and that room reaches the target temperature, it shuts off for the whole house. There are different levels of insulation across our house, so its difficult to find the one perfect place to put it. Plus we use the living room a lot during the day, and then not at all until morning.
I saw a video from the Energy Savings Trust that says to put the thermostat in the hallway. We don't usually heat ours, so if we did that our heating system would run all the time (unless programmed to be off). That sounds expensive, unless the cost can be mostly controlled with the radiator dials?
Is the answer to have the heating system always "on" during key times of day, and install smart radiator valves so the different rooms are kept at the right temperature despite their different uses and levels of insulation?
Oh, and should we be using our underfloor heating at all? What would be the point of installing two different heating systems?
Apologies for rambling. This is 100% the kind of thing I would normally ask my dad, but he doesn't live in the UK!
Just to add a bit of detail on the TRVs (the numbered valves on the radiators) - think of them as basically calibrating the temperature in that room relative to the room that your thermostat is in.
The best approach is to run your heating for a few hours (so every room has had plenty of time to heat up), and then go to each room in turn. If it feels cooler than you'd like, turn the radiator up a little. If it's warmer than you'd like, turn it down a bit. Then wait a bit and see if it's had the desired effect.
If you're not using a room most of the time (like a spare room or whatever), turn the radiator off or very low and keep the door shut. That saves a bit on heating bills.
If any of the radiators have an uneven temperature across their surface, or make gurgling sounds, bleed them.
You can invest in smart valves, but very few people here use them and they're probably only really worth it if you really care about each room hitting a precise temperature. You should be able to get things more or less comfortable across your house using your TRVs and a bit of trial and error.
posted by dudekiller at 7:40 AM on October 16, 2023 [4 favorites]
The best approach is to run your heating for a few hours (so every room has had plenty of time to heat up), and then go to each room in turn. If it feels cooler than you'd like, turn the radiator up a little. If it's warmer than you'd like, turn it down a bit. Then wait a bit and see if it's had the desired effect.
If you're not using a room most of the time (like a spare room or whatever), turn the radiator off or very low and keep the door shut. That saves a bit on heating bills.
If any of the radiators have an uneven temperature across their surface, or make gurgling sounds, bleed them.
You can invest in smart valves, but very few people here use them and they're probably only really worth it if you really care about each room hitting a precise temperature. You should be able to get things more or less comfortable across your house using your TRVs and a bit of trial and error.
posted by dudekiller at 7:40 AM on October 16, 2023 [4 favorites]
I'm in the US but this sounds like my heating system; the thermostat is in one room and controls the radiators for the entire house. Since you have a CHOICE of where to put the thermostat, I'd go for a room that is in the middle of the temperature range. You can use the underfloor heating if you're cold in a particular room, or turn up the thermostat.
On my radiators the valves do not make a huge difference but if yours do, extra bonus.
posted by metasarah at 8:04 AM on October 16, 2023
On my radiators the valves do not make a huge difference but if yours do, extra bonus.
posted by metasarah at 8:04 AM on October 16, 2023
Yes, thermostat in the hall set to something in the 16-21C range, adjust rooms using TRVs. You will have a radiator without a TRV, which helps make sure that the boiler continues to flow.
Normally you can also control the heating with a timer, so that it stays off when you're not in. If you're away overnight and it's properly winter (dipping below freezing) then you need to set the thermostat on but very low so that the pipes don't freeze. Because it's a temperate climate, the pipes can be in uninsulated spaces or outdoors, and frozen pipes break and can cause leaks.
Gas heating is always cheaper than electrical heating. Only use underfloor electric heating if you are still cold in that room even with the radiators on. If it's a room that you don't *have* to use, I would be tempted to close the door and accept that it will be cold in there.
posted by plonkee at 9:05 AM on October 16, 2023
Normally you can also control the heating with a timer, so that it stays off when you're not in. If you're away overnight and it's properly winter (dipping below freezing) then you need to set the thermostat on but very low so that the pipes don't freeze. Because it's a temperate climate, the pipes can be in uninsulated spaces or outdoors, and frozen pipes break and can cause leaks.
Gas heating is always cheaper than electrical heating. Only use underfloor electric heating if you are still cold in that room even with the radiators on. If it's a room that you don't *have* to use, I would be tempted to close the door and accept that it will be cold in there.
posted by plonkee at 9:05 AM on October 16, 2023
Best answer: Oh I had missed the fact that your existing thermostat might be portable (rather than that you're thinking of getting it moved).
If you get TRVs installed, it's important to keep the thermostat in a room that still has a dumb valve. Otherwise the thermostat will "fight" with the valve. The valve might switch off the radiator in that room, and then the thermostat will feel the cold and force the rest of the house to keep heating forever. It's also important not to get in a situation where ALL the radiators are off but the boiler is still pumping hot water around.
"Turn up the thermostat if you're cold" is only good advice if the thermostat already got up to your requested temperature. If the room is cold because it didn't finish heating yet, turning up the thermostat makes no difference now and just costs you money later.
Getting a smart meter (if you don't have one already) makes it easy to see the impact of your previous day's life choices on your electricity and gas bills, so you can adapt your habits more effectively.
posted by quacks like a duck at 9:07 AM on October 16, 2023 [1 favorite]
If you get TRVs installed, it's important to keep the thermostat in a room that still has a dumb valve. Otherwise the thermostat will "fight" with the valve. The valve might switch off the radiator in that room, and then the thermostat will feel the cold and force the rest of the house to keep heating forever. It's also important not to get in a situation where ALL the radiators are off but the boiler is still pumping hot water around.
"Turn up the thermostat if you're cold" is only good advice if the thermostat already got up to your requested temperature. If the room is cold because it didn't finish heating yet, turning up the thermostat makes no difference now and just costs you money later.
Getting a smart meter (if you don't have one already) makes it easy to see the impact of your previous day's life choices on your electricity and gas bills, so you can adapt your habits more effectively.
posted by quacks like a duck at 9:07 AM on October 16, 2023 [1 favorite]
Best answer: I have radiators in my old house. Many people get these serviced every other year, or if the system is deteriorating every year. Get a service scheduled.
Meanwhile - let's get familiar with your system! You may only need to bleed and balance the system for your comfort but there are several factors that make that a process, and you will want the system inspected regardless of its current operation. Check the documentation that you already have - it may be something buried in the stack of information.
Know that the thermal requirement demanded of each radiator are different - some rooms may require more heat than others, like spaces that open to the outside or are just leaky. A pro will only be able to guess at this - you need to sort out what is and isn't working. As noted, the control valves themselves degrade over time, so they may not actually be effectively controlling the radiator. A pro's time is money so identify which units are an immediate problem. Finally radiators over time will also vary in how much internal resistance they build up, which may or may not necessitate the whole system getting flushed out, but that should be reserved for if other actions don't address the issues.
You will need to map out your system - for example my house is a single 'zone' with a split circuit. The single zone means that there is only 1 thermostat and the whole system is either actively heating or not with only 1 pump driving the hot out into the radiators. This is the most simple type of setup with a very simple control system. Make note what the pressure gauge is reading when the system is off - I use my phone camera. Measure again when the system gets turned on, it should be significantly higher, and measure again after it has been running for at least 10 minutes. Low pressure has many causes, often they are not cheaply solved.
My circuit is split, with one line circling out the back half and the other circles out the front half. This means I could easily split my house into two zones, one for the front and one for the back if I wanted to invest in a fancier control system and second pump - and then I could control which zone, front or back, to actively heat and at what time of day. It is possible to have one thermostat and two zones so you will need to figure that out.
You will also need to label the valve that controls the water supply into the system. Mine is called a "Water Pressure Reducing Valve Boiler Feed Regulator" and these generally have distinctive bell shaped top and are connected to your houses cold water supply. Mine is a Bell & Gossett. Mine has a big tag on it so anyone can quickly be directed to it and turn it off. This is the very important. If the system ever starts to leak this is the part that you need to be able to control to limit more water from entering the system and pouring out into your house. Note: this unit might have been turned OFF and your system might be starved for water.
Once you have mapped out the circuit then go around and figure which units currently feel 'warm' and which ones are chilly. The chilly ones may have air trapped in them - get the special radiator key, track down the socket size (they vary) or if they look newer just use a screw driver and bleed the air valve on all of the chilly radiators. I do this every year.
My method: first grab an old rag and a bucket. Second, test that the air valves still work. Open the window in the room and then crack open the valve and then make certain you can close the valve back up . Second - actually purge the valves. Turn the system on, give it no more than 10 minutes or so to build pressure and then start at the units that are closest to the boiler on the circuit. Crack open the valve - listen to the air whistle out and marvel at how bad it smells. Water will start to spit out- so turn off the valve. Repeat at the next unit. And be careful because you might get hot blasting out.
Once all the air is out go around and just turn all the warm ones totally off and then check the system again in 4 or 5 hours. Add the chilly rooms by cranking on their control valves one at a time. Check that the handle is actually spinning the stem to close the valve. As the locals would say - you might to get a spanner on it. Tapping them gently, just a tap, with a hammer might assist stuck ones to get working.
If things are still unbalanced or just off you are ready to get a professional in. You will be able to hopefully identify which parts of the system are not working properly - stuck air valves, stuck control valves, and if it's a whole zone or a part of the circuit that appear to be non functional. If enough parts have failed then the system gets drained, parts replaced and then flushing the system is a trivial addition to that process.
There are a number issues not yet covered - and these are generally best left to a pro. For example, a professional has the tools that can check the systems overall pressure, and check at various spots in the system if that is necessary. The water circulation pump might not be up to the task - these eventually wear out or need refurbishing. Mine was making bad noises last year and got serviced. Your expansion tank might need to be serviced or replaced. This is something I've serviced, but is usually part of what a pro will check and you can just ask them to show you how to do it. The gauge on the boiler might not be reliable, along with the safety blow off valve, which has to be checked/inspected. The whole system also needs to be able to drain back into the boiler to work properly. And that means checking its grade, and while you might have a level this sort of problem is something I would just pay someone else to check and get correct. The boiler itself has a heat exchanger that is a high wear part and it needs regular maintenance to work properly. So it needs to be inspected.
If all of the chilly units are on the same part of the circuit or ideally their own zone then a pro can set that sort of system up to control that, but understand that this can be properly expensive.
posted by zenon at 9:15 AM on October 16, 2023 [3 favorites]
Meanwhile - let's get familiar with your system! You may only need to bleed and balance the system for your comfort but there are several factors that make that a process, and you will want the system inspected regardless of its current operation. Check the documentation that you already have - it may be something buried in the stack of information.
Know that the thermal requirement demanded of each radiator are different - some rooms may require more heat than others, like spaces that open to the outside or are just leaky. A pro will only be able to guess at this - you need to sort out what is and isn't working. As noted, the control valves themselves degrade over time, so they may not actually be effectively controlling the radiator. A pro's time is money so identify which units are an immediate problem. Finally radiators over time will also vary in how much internal resistance they build up, which may or may not necessitate the whole system getting flushed out, but that should be reserved for if other actions don't address the issues.
You will need to map out your system - for example my house is a single 'zone' with a split circuit. The single zone means that there is only 1 thermostat and the whole system is either actively heating or not with only 1 pump driving the hot out into the radiators. This is the most simple type of setup with a very simple control system. Make note what the pressure gauge is reading when the system is off - I use my phone camera. Measure again when the system gets turned on, it should be significantly higher, and measure again after it has been running for at least 10 minutes. Low pressure has many causes, often they are not cheaply solved.
My circuit is split, with one line circling out the back half and the other circles out the front half. This means I could easily split my house into two zones, one for the front and one for the back if I wanted to invest in a fancier control system and second pump - and then I could control which zone, front or back, to actively heat and at what time of day. It is possible to have one thermostat and two zones so you will need to figure that out.
You will also need to label the valve that controls the water supply into the system. Mine is called a "Water Pressure Reducing Valve Boiler Feed Regulator" and these generally have distinctive bell shaped top and are connected to your houses cold water supply. Mine is a Bell & Gossett. Mine has a big tag on it so anyone can quickly be directed to it and turn it off. This is the very important. If the system ever starts to leak this is the part that you need to be able to control to limit more water from entering the system and pouring out into your house. Note: this unit might have been turned OFF and your system might be starved for water.
Once you have mapped out the circuit then go around and figure which units currently feel 'warm' and which ones are chilly. The chilly ones may have air trapped in them - get the special radiator key, track down the socket size (they vary) or if they look newer just use a screw driver and bleed the air valve on all of the chilly radiators. I do this every year.
My method: first grab an old rag and a bucket. Second, test that the air valves still work. Open the window in the room and then crack open the valve and then make certain you can close the valve back up . Second - actually purge the valves. Turn the system on, give it no more than 10 minutes or so to build pressure and then start at the units that are closest to the boiler on the circuit. Crack open the valve - listen to the air whistle out and marvel at how bad it smells. Water will start to spit out- so turn off the valve. Repeat at the next unit. And be careful because you might get hot blasting out.
Once all the air is out go around and just turn all the warm ones totally off and then check the system again in 4 or 5 hours. Add the chilly rooms by cranking on their control valves one at a time. Check that the handle is actually spinning the stem to close the valve. As the locals would say - you might to get a spanner on it. Tapping them gently, just a tap, with a hammer might assist stuck ones to get working.
If things are still unbalanced or just off you are ready to get a professional in. You will be able to hopefully identify which parts of the system are not working properly - stuck air valves, stuck control valves, and if it's a whole zone or a part of the circuit that appear to be non functional. If enough parts have failed then the system gets drained, parts replaced and then flushing the system is a trivial addition to that process.
There are a number issues not yet covered - and these are generally best left to a pro. For example, a professional has the tools that can check the systems overall pressure, and check at various spots in the system if that is necessary. The water circulation pump might not be up to the task - these eventually wear out or need refurbishing. Mine was making bad noises last year and got serviced. Your expansion tank might need to be serviced or replaced. This is something I've serviced, but is usually part of what a pro will check and you can just ask them to show you how to do it. The gauge on the boiler might not be reliable, along with the safety blow off valve, which has to be checked/inspected. The whole system also needs to be able to drain back into the boiler to work properly. And that means checking its grade, and while you might have a level this sort of problem is something I would just pay someone else to check and get correct. The boiler itself has a heat exchanger that is a high wear part and it needs regular maintenance to work properly. So it needs to be inspected.
If all of the chilly units are on the same part of the circuit or ideally their own zone then a pro can set that sort of system up to control that, but understand that this can be properly expensive.
posted by zenon at 9:15 AM on October 16, 2023 [3 favorites]
Best answer: I missed the caveat that I am only familiar and have described above a low pressure water boiler system. These are common in old houses around here and from your description sound like what you have as well. There are a variety of high pressure and steam systems out there. Look up the boiler model online and it will provide information about its type.
posted by zenon at 12:14 PM on October 16, 2023 [1 favorite]
posted by zenon at 12:14 PM on October 16, 2023 [1 favorite]
The UK generally doesn't go for steam, at least. So you almost certainly have water filled radiators.
If any of them feel warm to only half way up they might have filled up with 'air' (god only knows what it is, but it usually smells eggy and horrible) and they need bleeding. This is a job you can do yourself with a radiator key and someone on YouTube to explain it, but if any water comes out of the bleed valve it's usually putrid and black, so make sure you have a collection of sad old towels around to stop it going anywhere else. Full radiators put out more heat.
posted by How much is that froggie in the window at 11:34 PM on October 16, 2023
If any of them feel warm to only half way up they might have filled up with 'air' (god only knows what it is, but it usually smells eggy and horrible) and they need bleeding. This is a job you can do yourself with a radiator key and someone on YouTube to explain it, but if any water comes out of the bleed valve it's usually putrid and black, so make sure you have a collection of sad old towels around to stop it going anywhere else. Full radiators put out more heat.
posted by How much is that froggie in the window at 11:34 PM on October 16, 2023
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If your boiler supports the OpenTherm protocol, get a thermostat that supports OpenTherm (e.g. 3rd gen Nest) and it will make the boiler more efficient by modulating the water temperature gradually as you need it instead of slamming the boiler between off and full blast.
British houses normally have a lot of thermal mass so they take a long time to heat and cool. The time it takes to heat the house will vary drastically depending on how much the temperature has dropped. If you get a Nest, it will calculate how far in advance to start the boiler for you based on how cold your house is.
There's no point using any of the "turn on the heating when you notice I've got home" features of smart thermostats, unless you want to freeze for two hours in winter while the house warms up.
Underfloor heating is normally hydronic, i.e. pipes full of water that make a kind of giant low temperature radiator. Often the pipes are in the concrete slab so they're warming all that nice thermal mass. They're more efficient than radiators, because most UK boilers are more efficient at low temperatures. People like underfloor heating because you get cosy toes, and because these days people like big open plan spaces where there's not many walls to put radiators on.
BUT the hydronic systems are hard to retrofit on old houses, because you can't sink the pipes in a concrete slab, and you can't easily raise the floor to go over the pipes. So sometimes, people who just like the idea of underfloor heating get sold the electric variety, possibly without realising that it's stupidly expensive to run (it was stupidly expensive even before the recent hike in electricity prices!). Normally the electric underfloor heating would just be used for a small bathroom or something. Definitely you should just leave it turned off unless you have more money then you know what to do with.
posted by quacks like a duck at 7:17 AM on October 16, 2023 [3 favorites]