Forced Hot Air Heating Efficiency

FreakShow!

Hi all,

I have just bought a house in the MIdlands, and the heating system is a little alien to me. It's a 'Forced Blown Air' heating system, which has vents into (nearly) all the rooms. I've only ever lived in a home that has had a combi boiler, so it's new to me.

Googling around, some people like it, some people hate it. I've not made up my mind on it yet.

One thing I'd be interested to know about is the efficiency of it. I think for heating the house, it's quite efficient, more so than a combi boiler. However, I can't find any actual facts/statistics/etc on this to back this up. It's just from reading other people's opinions on it (which there can be a heavy bias on!). But, the bigger problem is that the hot water is provided by an immersion heater with a hot water tank in. This is going to be a fairly expensive way of getting hot water for a number of reasons, such as hot water is produced when I might not need it (e.g. I have a lie-in one morning, don't have my regular hot morning shower), whereas as a Combi-Boiler will heat the water when I actually need it.

Does anyone have some actual stats etc to back any of my claims or refute them?

I'm thinking of getting quotes in on installing a Combi-Boiler and Radiators in the place, see the ball-park figure I'd be looking at.

Thanks.

tacpot12

I can't answer your specific query, but if you get on ok with the forced air heating, but want cheaper hot water, how about getting a combi boiler plus radiators only in the rooms that don't have hot air vents?

ThemeOne

Usually, though not invariably, hot air systems can be quite old - there was a vogue for it in the 70s then for whatever reason popularity waned. If that applies to your house, then it might not be the most efficient.

Personally I've always liked it, and it's still a popular system in Canada, and it copes well with their much colder winters.

With the immersion heater you say hot water could be heated when you don't need it, is that because it's on a timer? I find with my immersion I only need it on for about half an hour to have a decent shower, in other words if you have a variable routine, you can use it manually - you just have to try and think 30-60 minutes ahead.

silvercar

I'm thinking of getting quotes in on installing a Combi-Boiler and Radiators in the place, see the ball-park figure I'd be looking at.

You would also need to do something with the vents that you will no longer be using. You can't leave blocked off un-ventilated empty channels around the place.

FreakShow!

silvercar wrote: »

You would also need to do something with the vents that you will no longer be using. You can't leave blocked off un-ventilated empty channels around the place.

Yes. These would be removed where possible. There's probably a decent amount of storage space that will be freed up under the stairs, where all the ducting is hidden.

ThemeOne wrote: »

Usually, though not invariably, hot air systems can be quite old - there was a vogue for it in the 70s then for whatever reason popularity waned. If that applies to your house, then it might not be the most efficient.

Personally I've always liked it, and it's still a popular system in Canada, and it copes well with their much colder winters.

With the immersion heater you say hot water could be heated when you don't need it, is that because it's on a timer? I find with my immersion I only need it on for about half an hour to have a decent shower, in other words if you have a variable routine, you can use it manually - you just have to try and think 30-60 minutes ahead.

Well, that's just it, knowing what I need to be doing in the future! It's very much a convenience thing. I've read a lot about the heating system. Some love it, some hate it. Some like it, but say that the heat in the air can dissipate quickly, whereas Radiators retain the heat for longer. That's why the verdict is out on my opinion for now. But quotes will help decide if it's worth it or not. Only thing I can't find is relative efficiency. The heater must be at least ten years old. Will have to google the model.

tacpot12 wrote: »

I can't answer your specific query, but if you get on ok with the forced air heating, but want cheaper hot water, how about getting a combi boiler plus radiators only in the rooms that don't have hot air vents?

Seems a lot less efficient to have two systems.

ariba10

Why not suck it and see.

Try it for a few months and see how you get on with it?

GwylimT

We have central air, we have it set to 19 in the day and 12 at night, on hot days we set it to around 17 in the day time. We pay around £58 per month, but you have to remember our central air is used in the summer as well.

Yes radiators will stay hot longer, but they do take longer to heat a room, so its either get warmer a bit faster, or stay warmer a little longer after turning off. In our home the living area (open plan) has six vents. The bedrooms and bathroom have one. They're fairly small, come to think of it I don't know where we would put radiators!

FreakShow!

ariba10 wrote: »

Why not suck it and see.

Try it for a few months and see how you get on with it?

If I was to replace it, now is the time to do it, before I get furniture and everything in.

GwylimT wrote: »

We have central air, we have it set to 19 in the day and 12 at night, on hot days we set it to around 17 in the day time. We pay around £58 per month, but you have to remember our central air is used in the summer as well.

Yes radiators will stay hot longer, but they do take longer to heat a room, so its either get warmer a bit faster, or stay warmer a little longer after turning off. In our home the living area (open plan) has six vents. The bedrooms and bathroom have one. They're fairly small, come to think of it I don't know where we would put radiators!

£58 for heating. What about hot water?

r2015

I replaced my warm air heating with a combi and radiators and am saving about £160 a year in gas.


I should break even in about 37 years.

FreeBear

FreakShow! wrote: »

But, the bigger problem is that the hot water is provided by an immersion heater with a hot water tank in. This is going to be a fairly expensive way of getting hot water for a number of reasons, such as hot water is produced when I might not need it (e.g. I have a lie-in one morning, don't have my regular hot morning shower), whereas as a Combi-Boiler will heat the water when I actually need it.

The obvious solution would be an electric shower in the bathroom - Instant hot water for the shower when you need it. In the kitchen, it may be worthwhile looking at an under-counter water heater, either an instant-on-demand or one with a 5l/15l tank.

Got a fan assisted kickstrip heater in the kitchen, and I do like the warm air being blown around my feet. Unfortunately, it is plumbed in to the CH system, so I have to wait a while before the warm air starts coming out.

One thing with hot air heating systems that you might not have considered - In the summer months, they can be used to blow cooler air around the house (if your system is set up for that). Even if you decide to install a combi boiler & radiators, don't be too hasty in ripping out the ducting - You might want to use it for aircon in the summer.

GwylimT

FreakShow! wrote: »

If I was to replace it, now is the time to do it, before I get furniture and everything in.



£58 for heating. What about hot water?

Around £18 a month.