Radiator Booster - any thoughts?

don0301

whasup wrote: »

The device turns a passive convector radiator into a forced air convector. That will certainly make a room warmer because it will extract more heat from the radiator than would be extracted without it. But that heat will simply be replaced by the boiler, so the idea that the boiler will fire less is nuts. There is some value in being able to move heat around where and when you want it. From that point of view the device could be said to make the system more efficient. But this is very, very marginal and almost certainly not worth the cost. It is also true that the lower the return temperature in the system the more efficiently a condensing boiler will work. So taking heat out of the system does make the boiler more efficient. But that will also only be very marginal and again it's unlikely to cover the cost of the unit. Better option from a cost saving point of view would be to knock your programmer back by 10 minutes morning and night. No cost, no noise and will definitely save you money.

grahamc2003 wrote: »

Spot on I'd say. It can't save money in the sense most expect - as others have said, it MAY (then again it may not) save tiny amounts due to boiler efficiency changes - but this is such a tiny effect it would be unmeasurable imv, and well within the range of other factors affecting the efficiency (i.e. within the noise level).

Also, these only have an effect during the time the room warms up. It will cause the room to warm (a tiny bit) quicker (at the cost of more fuel burnt of course - it certainly isn't a 'free' effect) - but once at the target temperature, these will have no effect at all on the heat delivered overall, and will just affect the cycling of the boiler (very slightly).

There will also be another effect which no one's yet mentioned - and that is by cooling (bits of) the radiator surface, the radiant heat given off will be less, and that has to be offset from the extra heat delivered due to the forced convection.

rofl....


All the effects will be so tiny (especially any money saving, if any) I'd just use them if the warm air from the convection is diverted somewhere better for you (i.e. at you, instead of at the ceiling, where eddy currents usually take convected heat).

Room warms up quicker...thermostat temp. reached quicker....boiler turns off quicker....

or did i miss something?

zeupater

Hi

There are a couple of things which also need to be considered and they are linked ....

Firstly, whilst the radiator is the same size the forced convection draws more energy from it, which needs to be replaced by the boiler, so more energy is required per unit of time in order to heat the space ... and ... secondly, heating the air to a higher temperature more quickly simply increases the rate at which the heat is initially absorbed by the thermal mass.

No matter how quickly you inject the energy into the house to achieve an internal temperature a state of equilibrium will be sought by the laws of physics, therefore, for a level of external heatloss there needs to be a related level of heat replacement, else the thermal mass cools on each daily heating cycle .....

As long as raising the room temperature more quickly is seen as comfort solution and not an energysaving option it's fine, however it could be much more efficient (safer/cheaper) to simply replace the radiator with an oversized one and fit a thermostatic valve to compensate at the same time ...

HTH
Z

don0301

zeupater wrote: »

Hi

There are a couple of things which also need to be considered and they are linked ....

Firstly, whilst the radiator is the same size the forced convection draws more energy from it

isn't that the whole point?

, which needs to be replaced by the boiler, so more energy is required per unit of time in order to heat the space

it heats the space in a shorter time, and more efficiently....depending on cost of running said unit?

... and ... secondly, heating the air to a higher temperature more quickly simply increases the rate at which the heat is initially absorbed by the thermal mass.

No matter how quickly you inject the energy into the house to achieve an internal temperature a state of equilibrium will be sought by the laws of physics, therefore, for a level of external heatloss there needs to be a related level of heat replacement, else the thermal mass cools on each daily heating cycle .....

As long as raising the room temperature more quickly is seen as comfort solution and not an energysaving option it's fine, however it could be much more efficient (safer/cheaper) to simply replace the radiator with an oversized one and fit a thermostatic valve to compensate at the same time ...

I just read Sir Humphrey

HTH
Z

oh dear...Sir Humphrey....

if it's cheap to run, and spreads the heat from the radiator, in a good way, whats the downside?

a modern home with av. room sizes prob won't need.

other homes i think worth considering.

don0301

zeupater wrote: »

Hi

There are a couple of things which also need to be considered and they are linked ....

Firstly, whilst the radiator is the same size the forced convection draws more energy from it, which needs to be replaced by the boiler, so more energy is required per unit of time in order to heat the space ... and ... secondly, heating the air to a higher temperature more quickly simply increases the rate at which the heat is initially absorbed by the thermal mass.

No matter how quickly you inject the energy into the house to achieve an internal temperature a state of equilibrium will be sought by the laws of physics, therefore, for a level of external heatloss there needs to be a related level of heat replacement, else the thermal mass cools on each daily heating cycle .....

As long as raising the room temperature more quickly is seen as comfort solution and not an energysaving option it's fine, however it could be much more efficient (safer/cheaper) to simply replace the radiator with an oversized one and fit a thermostatic valve to compensate at the same time ...

HTH
Z

really?

Ben84

Might be useful for boosting heat output in rooms that you'd like hotter when the heating is on. Many old heating systems have undersized radiators. However, this would cause your boiler to burn more, not less gas! So, it has a use, but not really the one it's being marketed for.

don0301

Ben84 wrote: »

Might be useful for boosting heat output in rooms that you'd like hotter when the heating is on. Many old heating systems have undersized radiators. However, this would cause your boiler to burn more, not less gas! So, it has a use, but not really the one it's being marketed for.

??

isnt the whole point of it to make the radiator more efficient?

ie to heat the room more efficiently??

in a modern home, I'd argue not worth it, rooms heat quickly

otherwise? def something i would look at....

Ben84

don0301 wrote: »

??

isnt the whole point of it to make the radiator more efficient?

ie to heat the room more efficiently??

in a modern home, I'd argue not worth it, rooms heat quickly

otherwise? def something i would look at....

Efficient can have multiple meanings.

The radiator would transfer heat more efficiently when you pump air against it, but it's not the radiators where the energy loss from your heating system occurs - that happens in the boiler. What pumping air against the radiator does however do is remove more heat from the radiator, so you can heat the room faster and to higher temperatures than before. Of course, this heat has to be accounted for so more gas is burnt in the boiler.

Main point is that your boiler's efficiency at transferring heat to the radiators remains the same, all this device does is allow you to extract more heat from a radiator.

Martyn1981

Ben84 wrote: »

Efficient can have multiple meanings.

The radiator would transfer heat more efficiently when you pump air against it, but it's not the radiators where the energy loss from your heating system occurs - that happens in the boiler. What pumping air against the radiator does however do is remove more heat from the radiator, so you can heat the room faster and to higher temperatures than before. Of course, this heat has to be accounted for so more gas is burnt in the boiler.

Main point is that your boiler's efficiency at transferring heat to the radiators remains the same, all this device does is allow you to extract more heat from a radiator.

I can see your point that there is little net effect either way, but that is assuming we are happy to heat long and slow.

Obviously impossible, but a better heating solution would be, you switch it on and warm, you switch it off and cold, a bit like a light switch.

So, if you heat the room air quickly (and comfortably), then that has to be better than slowly raising the thermal mass of the room, especially when 8 or 9pm comes round and your body needs to start cooling down to help with natural body and sleep rhythms. At that point, the more heat stored in the structure, the more that will leak away during the night.

Never really considered this issue till we added an extra rad to living room, went from 900mm double, to total 1400mm double. Room now takes 15mins, not 2 hours to heat up - obviously only air, rather than slowly heating thermal mass. Also, the opposite is now true, cools down much quicker, unless heating on all day.

So better to make the room air comfortable quickly for occupants, rather than heat the whole structure if rooms not being occupied continuously. However, in a long cold winter, of many days, even weeks of continuous cold, the net difference would be zero.

Best solution, as all have said, is large efficient rads, with suitable boiler, but 'forcing' more heat from rads quicker can be beneficial, as a faster way of converting gas to heat, if the boiler is up to it. After all most people aren't looking for a mathematical approach to total overall efficiency, they simply want comfort as fast as possible.

Mart.

zeupater

Martyn1981 wrote: »

I can see your point that there is little net effect either way, but that is assuming we are happy to heat long and slow.

Obviously impossible, but a better heating solution would be, you switch it on and warm, you switch it off and cold, a bit like a light switch.

So, if you heat the room air quickly (and comfortably), then that has to be better than slowly raising the thermal mass of the room, especially when 8 or 9pm comes round and your body needs to start cooling down to help with natural body and sleep rhythms. At that point, the more heat stored in the structure, the more that will leak away during the night.

Never really considered this issue till we added an extra rad to living room, went from 900mm double, to total 1400mm double. Room now takes 15mins, not 2 hours to heat up - obviously only air, rather than slowly heating thermal mass. Also, the opposite is now true, cools down much quicker, unless heating on all day.

So better to make the room air comfortable quickly for occupants, rather than heat the whole structure if rooms not being occupied continuously. However, in a long cold winter, of many days, even weeks of continuous cold, the net difference would be zero.

Best solution, as all have said, is large efficient rads, with suitable boiler, but 'forcing' more heat from rads quicker can be beneficial, as a faster way of converting gas to heat, if the boiler is up to it. After all most people aren't looking for a mathematical approach to total overall efficiency, they simply want comfort as fast as possible.

Mart.

Hi

Consider that the room is a living space and therefore would likely not be the one with the thermostat as is the case in most installations .... forced convection over the radiator will deliver more heat and raise the temperature in the room more quickly, therefore, if there is no automated thermostatic control on the forced air device then the room will not only be raised to the desired temperature more quickly, but it will continue to provide more heat after the balanced/designed temperature has been reached .... result, more energy expended (however I doubt that much more heat would be drawn from the radiator by a couple of small PC fans).

Depending on the size and type of the current radiator/room a replacement larger radiator including a thermostatic control should be well under £100 and could deliver between 2x and 2.5x the heat whilst covering the same wallspace (Type 22 replacing Type 11 & type 10 respectively) ..... that would be my first consideration, unless the fans were particularly large or powerful, which PC fans aren't.

HTH
Z

Martyn1981

zeupater wrote: »

Hi

Depending on the size and type of the current radiator/room a replacement larger radiator including a thermostatic control should be well under £100 and could deliver between 2x and 2.5x the heat whilst covering the same wallspace (Type 22 replacing Type 11 & type 10 respectively) ..... that would be my first consideration, unless the fans were particularly large or powerful, which PC fans aren't.

HTH
Z

Z - Let's not fool ourselves, adding small fans is no great solution, and as I said, large efficient rad every time. However, whilst I'd agree that a large double rad, a TRV and a set of valves can be got for £100, most people would have to employ a plumber too, and for a nuisance job like this, that would be 1/2 day's pay. For some that expense may be hard to swallow (they should, but maybe can't).

Long term, new rad as rooms get re-decorated, or whole new system if required and finances allow. But short-term, anything that helps heat the room, well air, quicker is a bonus. Though that bonus may be on the very small side!

Mart.