Heating the house: radiators & multi fuel stoves

B0bbyEwing

Strap in because there's a lot of wondering going on in my head at the moment which I want to get out.

1. If you're not sure about something - ask.
2. "you're over thinking" - nope not really. I'm looking at the possibility of reducing cost and besides, these questions will have answers & if simply asking them offends anyone then that's worrying.
3. I have a Worcester combi boiler & one of those fires which everyone calls a multi fuel stove that has a closed door so it's not an open fire. As such this whole thread is about these things and not any other kind of boiler or fire you may have. 
4. The fire doesn't heat the water. Unfortunately it also doesn't heat upstairs. It pretty much only heats the living room. I suppose it'll heat the kitchen/diner a little and the hall but not so much.

Right now I'm in the situation where I get my wood for free so on that note, central heating vs fire is a no brainer in winter - get the fire on. I typically don't put it on on a weekday as by the time we get home from work, it'd only be on 6pm - 9pm at the very most but with the cost of energy shooting up I may have to start doing that which has the knock on effect of I would probably be using the wood quicker than I can get it & therefore need to buy a jumbo bag of logs

which then complicates the cost question.

Now to get cost of running the fire, only way I can think of is say the bag costs £50 and you have 50 logs then you just count how many logs you burned that day. 10 logs - cost you £10 to heat the room that day.

Central heating - I've no idea how you'd calculate what it cost to heat the house on a given day so therefore I can't compare. Do you guys know how to work this out?


On the topic of central heating, a few questions:

1. Heat all rooms or only the ones you're in - and any negative impact of doing that? If heating only what we'd be in then it'd only be living room & bedroom being heated really. Kitchen/diner not much point as the oven would be on. Hall - who cares. Spare bedroom - well, it's spare. Box room - who cares. Or is that a false economy (thinking on the lines of similar to osmosis) where the heat will keep escaping from the rooms you're heating to balance out the colder joining rooms that will be many degrees lower. PLUS, if you're never heating certain rooms, does that negatively impact the radiator in any way (thinking on the lines of a cars A/C system - things dry out) not to mention the damp?
2. Someone once told me years ago that even during summer you should put the radiators on for a "quick blast" because (his words) "people then wonder why they have leaks when they come to it in winter when it hasn't been used for 6 months". Is there something to what this guy said or is that codswallop? 
3. This winter gone I already tried turning the TRVs down on the radiators themselves, as well as the actual number on the gizmo that's attached to the wall where you set the temperature. I did used to just have all radiators set to full whack. Some are now at "3" while others are at "4". What I've noticed is that some radiators do still get warm when set at "3", however some (such as the small one in the box room and the larger one in our bedroom - both single panel rads) still feel stone cold at "3". You need to turn them up to 4 and then you hear the water gushing through them & they then warm up.

I think that's it for the wondering. In summary what we currently do (in winter) is use the fire at the weekend, turn the rads in the living room completely off but have all other rads in the house on.

And what I'm here right now for is because I assume there's a better/more efficient way of heating the home with what I currently have, so I'm looking to see what that is in order to reduce what I'm spending on heating the home, even though a big change could be having to move from getting free wood to paying for it. That isn't a 100% cert yet but it's a possibility.

FreeBear

Are your radiators balanced properly ?

That would be the first thing to look at if some radiators are not heating up from cold as you'd expect.

As for wood, you are wasting money by getting logs delivered in bulk bags - Much better to get a loose load tipped, and then stack it somewhere dry. Preferably, buy in logs during the summer so that they have a chance to dry out a bit more. Stored in a bulk bag, the logs won't be getting any air, so won't dry out. And if it rains, they get wet, and stay wet (if stored outside).

thriftytracey

We use a multi fuel stove to heat one room.  We spend about £250 a year on logs and a few bags of taybrite smokeless coal.  We light the stove in the afternoon during the winter.  We don't have the heating on at all during the winter, relying on a small electric heater in the bathroom and one in the kitchen.  We are retired now so don't have the larger income to pay for GCH and would rather use the money saved for holidays.  We are still relatively young, in our 60's and tend to do lots of activities in the mornings during winter.  When we age and become infirm it will be different. I expect we would need to downsize and hopefully release some equity to pay the heating bills! 

At least we have supplementary pensions - its awful to think of pensioners having to manage solely on their state pension.  Well, quite honestly they won't manage.  The elderly will get ill and even die.  

I've researched solar panels + battery but they require a large capital outlay, we don't have huge savings so reluctant to go down that path.

Alnat1

The numbers on a TRV relate to a temperature. If the room is below that temperature, the radiator will heat up. Once the room is warm enough, the valve closes and the radiator will cool down. Different makes and models vary slightly as to what temp each number relates to but as a general idea see below. Valve position Reference temperature * 6°C 0-1 12°C 1  15°C 2 17°C 2-3 18°C 3 19-20°C 3-4 20-21°C 4 22°C 5 max.

[Deleted User]

There is no 'simple' way to calculate how much energy you will need to heat a house in a given day as there are a number of ever-changing factors. For example, it costs nothing to heat a house to 21C on a day when the outside temperature is 21C whereas it costs a lot to heat a home when the outside temperature is, say, Minus 2. On a bright sunny day you also get solar effects through the windows.

A house is an insulated box. Some boxes are better insulated than others. A house will only heat up and stay at a set temperature when heat in equals heat out. If you leave rooms without heat, then they will act as a cold soak and take heat from the rooms that you do heat. They are also attract the moisture that is in every home and, over time, walls can get damp and become mouldy. We set all our TRVs to come on if the room temperature drops below 13C - which in a well insulated home is unusual even in a cold snap. The settings on the TRVs equate to the following temperatures:

• 0 = Off.
• * = 7°C.
• 1 = 10°C.
• 2 = 15°C.
• 3 = 20°C.
• 4 = 25°C.
• 5 = 30°C.

The reason why the radiators are stone cold is because the room is at the set temperature. Instinctively, you feel cold because the radiator is cold.

It is also worth looking at your combi boiler flow temperature settings. For maximum efficiency, the boiler flow temperature needs to be as LOW as possible. You will still get hot water.  Yes, the house will take longer to reach the temperatures that you have set; however, most boilers - even on their lowest modulation setting - are massively oversized for maintaining a set temperature in a house.

The problem with running a boiler on just one or two radiators is that the return flow temperature will end up being pretty close to the flow temperature. A properly balanced heating system is designed to have a 20C fall between the flow and return temperatures: if not the boiler will stop heating but the pump will continue to run to dissipate heat from the heat exchanger: this is known as "cycling". If the return flow temperature is >56C, then the boiler is not condensing; ie, it is not removing latent heat from the flue gases (see Dew Point). A recent industry survey concluded that most condensing boilers rarely ever condense. People think that great plumes of white steam mean that coindensing is taking place whereas there should only be a whisp of steam and frequent purges of the boiler syphon.

B0bbyEwing

FreeBear said:

Are your radiators balanced properly ?

That would be the first thing to look at if some radiators are not heating up from cold as you'd expect.

No idea. Wouldn't know how to tell.

I know the whole thing needed sorting some years ago & the plumber installed a mini magna-clean thing and was beating the radiators. 

They were fine for some time after but just noticed that "3" doesn't warm up some of them yet "4" will whereas on others, "3" is fine. 

I also suspect there's a leak but just don't know where. I don't know how quickly a system should drop to under 1 bar from 1.5 bar but I'm having to pressurize the system every x-amount of months. I should really figure out the time between.

FreeBear said:

As for wood, you are wasting money by getting logs delivered in bulk bags - Much better to get a loose load tipped, and then stack it somewhere dry. Preferably, buy in logs during the summer so that they have a chance to dry out a bit more. Stored in a bulk bag, the logs won't be getting any air, so won't dry out. And if it rains, they get wet, and stay wet (if stored outside).

While you're correct, this quote misses the point.

So yeah, it's more efficient loose than in bulk bags but the basis is the exact same - I would still be looking at comparing the price of paid for wood vs central heating instead of the situation I've got now. It's just that it'd be cheaper than in bagged form.

If I was to buy, I actually would've got them loose anyway & put them in my log store, but I didn't think we'd be getting in to that side of things as it wasn't really key to my question.

B0bbyEwing

thriftytracey said:

We use a multi fuel stove to heat one room.  We spend about £250 a year on logs and a few bags of taybrite smokeless coal.  We light the stove in the afternoon during the winter.  We don't have the heating on at all during the winter, relying on a small electric heater in the bathroom and one in the kitchen.  We are retired now so don't have the larger income to pay for GCH and would rather use the money saved for holidays.  We are still relatively young, in our 60's and tend to do lots of activities in the mornings during winter.  When we age and become infirm it will be different. I expect we would need to downsize and hopefully release some equity to pay the heating bills! 

At least we have supplementary pensions - its awful to think of pensioners having to manage solely on their state pension.  Well, quite honestly they won't manage.  The elderly will get ill and even die.  

I've researched solar panels + battery but they require a large capital outlay, we don't have huge savings so reluctant to go down that path.

Similar situation to my mother. Halogen heater in the bathroom 10mins or so before anyone uses it. Central heating not on so much. Fire going for good chunks of the day. Unlike me, she has to pay for her wood. 

Really is a sad state when we're having to look at it like this. It's like we've gone back 200 years.

B0bbyEwing

Alnat1 said:

The numbers on a TRV relate to a temperature. If the room is below that temperature, the radiator will heat up. Once the room is warm enough, the valve closes and the radiator will cool down. Different makes and models vary slightly as to what temp each number relates to but as a general idea see below. Valve position Reference temperature * 6°C 0-1 12°C 1  15°C 2 17°C 2-3 18°C 3 19-20°C 3-4 20-21°C 4 22°C 5 max.

Ahh, so what you're saying then (are you?) is that if some rads are kicking in on "3" downstairs but those upstairs aren't, then if the room temperature is equal to or higher than the setting for "3" then the rad wont heat up anyway?

QrizB

B0bbyEwing said:

So yeah, it's more efficient loose than in bulk bags but the basis is the exact same - I would still be looking at comparing the price of paid for wood vs central heating instead of the situation I've got now. It's just that it'd be cheaper than in bagged form.

We discussed this on the "other fuels" sub-forum last winter.

Try this thread:
https://forums.moneysavingexpert.com/discussion/6332445/firewood-price-guide/p1

If dry logs contain 4kWh/kg, and gas is 15p/kWh, your target price for dry logs is under 60p/kg. If a cubic metre of dry logs weighs 300kg, that's £180 per cubic metre.

B0bbyEwing

[Deleted User] said:

There is no 'simple' way to calculate how much energy you will need to heat a house in a given day as there are a number of ever-changing factors. For example, it costs nothing to heat a house to 21C on a day when the outside temperature is 21C whereas it costs a lot to heat a home when the outside temperature is, say, Minus 2. On a bright sunny day you also get solar effects through the windows.

Well yes, but I'm not talking about 21c outside, I specifically said winter when it's cold & wet outside. 

A bit like when I asked about drying clothes in winter in the other thread & someone came in talking about this time of year. I'm thinking ..........why?!

[Deleted User] said:

A house is an insulated box. Some boxes are better insulated than others. A house will only heat up and stay at a set temperature when heat in equals heat out. If you leave rooms without heat, then they will act as a cold soak and take heat from the rooms that you do heat. They are also attract the moisture that is in every home and, over time, walls can get damp and become mouldy. We set all our TRVs to come on if the room temperature drops below 13C - which in a well insulated home is unusual even in a cold snap. The settings on the TRVs equate to the following temperatures:

• 0 = Off.
• * = 7°C.
• 1 = 10°C.
• 2 = 15°C.
• 3 = 20°C.
• 4 = 25°C.
• 5 = 30°C.

The reason why the radiators are stone cold is because the room is at the set temperature. Instinctively, you feel cold because the radiator is cold.

First half of that - So what you're saying then is that it's beneficial to heat the house rather than individual rooms (or are you?)? 

So if we're not using the spare room, it doesn't matter - have it set so it equals the rest of the house, that way there's no cold soak (& damp)?

Last bit of that quote - ah so that ties in with what I just responded to Alnat1 with (in case it's not obvious, I'm replying to posts as I read them).

[Deleted User] said:

The problem with running a boiler on just one or two radiators is that the return flow temperature will end up being pretty close to the flow temperature. A properly balanced heating system is designed to have a 20C fall between the flow and return temperatures: if not the boiler will stop heating but the pump will continue to run to dissipate heat from the heat exchanger: this is known as "cycling". If the return flow temperature is >56C, then the boiler is not condensing; ie, it is not removing latent heat from the flue gases (see Dew Point). A recent industry survey concluded that most condensing boilers rarely ever condense. People think that great plumes of white steam mean that coindensing is taking place whereas there should only be a whisp of steam and frequent purges of the boiler syphon.

Not sure what that means to be honest. Also don't know whether it means carry on doing what I'm doing or make a change or what. Totally gone over my head. Not your fault, I just don't grasp it.



So after all that it seems that I think only my second #2 hasn't been answered - in what that guy told me about giving your rads a blast through the summer.

Oh & also whether any negative effect on the rads occurs when you're not using them, which kind of is what I just asked about. What I'm thinking of with this one is a little different from not using them for 6 months through summer but more using all the other rads in the house & turning the living room ones off due to the fire being used.

[Deleted User]

A combination boiler is usually a condensing boiler. Condensing boilers are only truly efficient if they are condensing: that is, the water returning to the boiler must be at a temperature of 56C or less. The lower the return temperature the higher the efficiency. High efficiency equals less usage of gas. Look at the graph: if the return temperature is 56C then your boiler will be 87% efficient. If you can tolerate a boiler flow temperature of 50C and the return temperature is 30C, then your boiler efficiency increases to c.96%.  If your return flow temperature is above 56C, then this is above the Dew Point and no condensation can occur.

The problem with turning off most of the radiators is that your large heating system becomes a very small heating system. The water from your boiler returns at almost the same temperature as it left so little condensing occurs so your boiler is inefficient. 

My comment about 21C outside and 21C inside is that your heating requirement varies as the difference between the inside and outside temperatures increases. If the outside temperature is 10C, you will use a lot less energy to heat your home to 21C than you would if the outside temperature was minus 2C.

I live in a 4 bedroomed house and we have the heating on from 7am to 9pm with a boiler temperature of between 55 and 65C (higher if it is very cold). I adjust the boiler flow temperature manually but you can buy a weather compensation device. Our TRVs are set at 2 in unused rooms and 3 elsewhere with thermostats set at 19C. Our gas usage over the last 12 months was 7639kWh.

The ‘blast through the summer’ reference is your plumber’s way of telling you that zone valves and TRVs have a habit of sticking when they are not used. It is always good practice to turn up the thermostat once a month.

Finally, if radiators are slow to heat up then it could be down to a build up of sludge in the radiators. Water contains air, and air and metal cause rust. Check the colour of the water that comes out of a vent plug. If it is dirty, then you need to drain your system; refill it with water and a cleaner; flush, and refill with water and an inhibitor. If there is a leak present, then each time you top up the boiler pressure, you are introducing more air into the system.