Balancing Rads
- Thread starter diynoob
- Start date
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If you assume a worst case scenario (uninsulated floor, walls and ceiling) you would need 8.2kW if the chimney is open, but only 6.8kW if the chimney is open. This is due to the increased air circulation.
1. Blocking the chimney would save 1400W
2. Insulating the roof would save 1400W
3. Insulating the walls would save 950W
4. Insulating the floor would save 800W
5. Double glazed UPVC windows and doors would save 570W
Item 1 costs virtually nothing
You can get grants for Item 2 and 3 (do the whole house while you are about it), but probably not for item 4.
Items 1 to 4 would save 3,650W and cost £500 or less to do.
Items 5 would save 570W and cost about £2K.
1. Blocking the chimney would save 1400W
2. Insulating the roof would save 1400W
3. Insulating the walls would save 950W
4. Insulating the floor would save 800W
5. Double glazed UPVC windows and doors would save 570W
Item 1 costs virtually nothing
You can get grants for Item 2 and 3 (do the whole house while you are about it), but probably not for item 4.
Items 1 to 4 would save 3,650W and cost £500 or less to do.
Items 5 would save 570W and cost about £2K.
Are they doubles of 2300 long?
What temperature could you achieve during the coldspell of minus 8-10?
2 rads, they are both the double finned ones and are 60cm high. One is 190cm long and the other is 95cm long.
I don't know, I've only lived in the house 1 week!
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You currently have about 5 kW output under standard measuring conditions, so your estimate was pretty close.
In your case, heatloss calculations are pretty pointless for a number of reasons. The main one is, that you could double the size of your rads in the lounge, it wouldn't make any difference.
Your problem is not the size of the rads, but the fact that your roomstat is in the wrong place.
Putting it in the hall worked fine in the sixties when the heating was only on for an hour in the morning and a couple of hours in the evening. It was effectively use to get the chill out of the house and people wore woollies most of the time.
Today, we want a bit more comfort and have the heating on many more hours a day. As a result, the roomstat should be placed in the lounge, with trv's on the rads in other rooms.
At the end of the day, if the hall is a bit too cold, who cares? You don't spend your time in the hall, but in the lounge.
In your case, heatloss calculations are pretty pointless for a number of reasons. The main one is, that you could double the size of your rads in the lounge, it wouldn't make any difference.
Your problem is not the size of the rads, but the fact that your roomstat is in the wrong place.
Putting it in the hall worked fine in the sixties when the heating was only on for an hour in the morning and a couple of hours in the evening. It was effectively use to get the chill out of the house and people wore woollies most of the time.
Today, we want a bit more comfort and have the heating on many more hours a day. As a result, the roomstat should be placed in the lounge, with trv's on the rads in other rooms.
At the end of the day, if the hall is a bit too cold, who cares? You don't spend your time in the hall, but in the lounge.
Thanks, it's very useful seeing it written down like that. Seems like a no-brainer to get 1-4 done first.
Don't get your hopes up too much. Though insulation and draft proofing are useful exercises, the figures are wrong.
Dhailsham is not a pro, but a householder who gets his knowledge mainly from googling government publications and manuals.
The figures displayed amount to more than the output of the rads in your lounge, which is impossible. Insulation does not produce heat, i.e. you can not save 5000 Watt if you only produce 4500.
Small point, aren't the reductions quoted more to do with heating design than existing heat output? The aim is to bring the heating requirement below the available heat output. Of course, it might be possible to increase the radiator size instead. A householder's first consideration is usually to their wallet. What solutions can be afforded immediately and will cost least in the long run?
Depends how you look at it. But when figures suggest that you can save more heat than is produced, you know that there is something seriously wrong with the calculation.
Even if the figures were "only" 100% too high, it would mean the room was far too cold e.g. 14 degrees, in stead of a bit too cold.
Doubling the radiator size would make no difference; it's not primarily an output problem, but a flawed control system. It is not the house that is too cold, but one particular room. This is typically the kind of thing where google heroes tend to go flat on their face. They have never designed, nor installed a control system and do not recognise the cause of the problem.
Sound principle, provided that the money you spend actually brings the solution you are looking for.
New tyres on the car may improve reliability or safety, I doubt it will do a lot for your fuel consumption.
You are misinterpreting my figures. The saving I am quoting is the reduction in the required rad size when each option is implemented, assuming that the worst case requires 8.2kW. Maybe I could have explained it better. Does this help?
1. Blocking the chimney will reduce the required rad by 1400W
2. Insulating the roof will reduce the required rad by 1400W
3. Insulating the walls will reduce the required rad by 950W
4. Insulating the floor will reduce the required rad by 800W
5. Double glazed UPVC windows and doors will reduce the required rad by 570W.
If we ignore no 5 as not being cost effective, the total reduction is 4.45kW
The rad size before implementation was 8.2kW, so the rad size after would be 8.2 - 4.45 = 3.75kW, which is less than the 5kW your existing rads produce.
Yes I agree the results won't be as much as quoted. Still, I believe these steps will reduce the heating requirement for a very small cost.
If instead I take your suggestion and pay for the stat to be moved from the hall to the lounge. That doesn't alter the fact the the lounge is 8C colder than every other room in the house. It also doesn't affect the situation that I have approx 5kW output in a room with approx 7kW requirement.
I currently have the stat on 25C with a living room temperature of 17C. If I move the stat to the lounge then I could set the stat to 17C to achieve a 17C lounge temperature. But wouldn't my heating bill would be the same? Isn't the boiler doing the same amount of work in a futile attempt to heat up the lounge?
And you could set the stat in the lounge to 25C, but it would never reach that temperature because the radiators are not large enough for the heat loss. The only possible solutions are:
1. Reduce the heat loss; and/or
2. Increase the rad sizes (assuming the boiler has the capacity).
As for the location of the room thermostat. It doesn't matter where it is, provided each room has the correct size radiator.
Without being on site, it is impossible to say what the best order of action is, apart from one thing.
Block the chimney off completely, and disable any appliances that use it. Now you can also block the ventilation openings that have thus become obsolete. The cost is virtually nil, and the heatloss through chimney plus ventilation openings can be huge.
If your room is indeed 8 degrees colder than any other room, there is something very wrong, or better said: various things are wrong.
Rough rule of thumbs shows the second 8 degrees will take twice as much as the first 8 degrees temperature rise, which means you would need 15 kW output just for the lounge; twice as much as the calculation.
Heatloss calculations are not too exact, nor too reliable, but 100% off is too much.
Block the chimney off completely, and disable any appliances that use it. Now you can also block the ventilation openings that have thus become obsolete. The cost is virtually nil, and the heatloss through chimney plus ventilation openings can be huge.
If your room is indeed 8 degrees colder than any other room, there is something very wrong, or better said: various things are wrong.
Rough rule of thumbs shows the second 8 degrees will take twice as much as the first 8 degrees temperature rise, which means you would need 15 kW output just for the lounge; twice as much as the calculation.
Heatloss calculations are not too exact, nor too reliable, but 100% off is too much.
I could not have given a better example of the difference between a google hero and a pro, if I had tried.
Well it's tricky to decide what to do with completely contradictory advice!
I've blocked up the chimney and balanced the rads since that costs nothing.
Next is to either get the walls and floors insulated or get TVRs fitted and move the thermostat. The arguments for insulation, thus reducing the heat requirement of the lounge seem more logical and compelling.
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