Types of central heating

[Andeh13]

I am now more or less settled in a house, but one of the understandings of me living here is the fact that I need to renovate some areas of it. One of which is the central heating system. Currently there is a warm air system, which uses vents in all of the room instead of radiators. I am reading mixed views on it's efficiency compared to a normal radiator based system.

Currently the warm air system is ancient(built in with the house) & we were advised to look at sorting it by the previous owners. I want to try and get it done this side of Christmas, I don't have reliable hot water (taps only, showers electric) which is driving me mad. My query is whether it's worth replacing it with a conventional system or a newer warm air system.

A full central heating & radiator setup is going to cost around £3,500 give or take some for the full system, I am getting a few more quotes but that is the general price I have been told to expect. I imagine a warm air system would be considerably cheaper as it would just need a new central unit.

My concern is the efficiency of both setups. I'm going to be here for several years and I don't want to install a white elephant only to regret it each winter. Does anyone have any experience with warm air systems, who could offer some advice on how they find it?

Many thanks guys

[scaryjim]

There's some decent eco-friendly warm air systems available and you used to be able to get grants to help with the installation costs. The problem with having a new boiler + rads system put in is that you're talking a LOT of disruption and mess. Personally, I'd be much more inclined to look at the warm air systems.

As far as efficiency goes, iirc conventional systems are reckoned to be less efficient than a decent condensing combi boiler, but advances may have been made in the 5 years since I stopped working in household energy efficiency As I say, purely in terms of minimal disruption my first port of call would be upgrading the warm air system, and I'd do some research into eco-friendly possibilities - there certainly used to be possibilities in terms of solar warm air. I seem to remember that was a really clever solar warm air system that could be reversed in the summer to provide an element of AC as well, but as I say it was 5 years ago and I could be remembering wrong... definitely what I'd look at first though.

EDIT:
By the way, dude, you really need to learn to use google

http://www.johnsonandstarley.co.uk/w...r/overview.asp are the UKs leading warm airt specialist according to most sources including NEF. Apparently you can get condensing boilers to use with warm air systems, and apparently modern warm air systems are reckoned to be on a par with, if not better than, comparable rad-based systems.

[Andeh13]

Yeh, I am inclined to agree, Radiators require a lot of pipes running along the base of walls (can't go under the floors) which I wasn't such a big fan of.

I would like the warm air system to be plugged into the taps so it produces the hot water on demand (no storage heater?) but I am not sure of how this would work/if it's possible? Is that a combi boiler?

[Flibb]

theres a bit of info on warm air here
http://www.miketheboilerman.com/warmair.htm

[oolon]

Air Duct systems react very quickly to a change of temperature, so it can get warm very quickly as the cold air from the room is removed and replaced with warm air likewise when the system goes off as soon as the air goes away. As a radiator is a big lump of metal with water in it there is a lot of heat stored in the radiator after the system goes off. One of the advantages of an air based system is you can cool rooms down as well as heat them up as air is remove from the rooms as well if a room gets to hot the hot air will be removed and replaced with colder air!

Both system take about the same amount of energy to heat a house, looking at your boiler is the thing to do, gas systems are the cheapest to run as per kW of entry it is cheapest, if you have an electric system, looking at a ground source heat pump is the thing to do. An electric fire turns electricy into heat, a ground source heat pump does something with the energy first... ie pull heat from somewhere else so is more efficient. But still not cheap than gas!

If I was replacing the system I would look at under floor heating this makes the room feel warmer for the people in it by putting the heat near the floor, air based system heat from the top down. The heat level is at a lower level so less is lost to the environment getting the the rooms as the loss is prepositional the temperature difference. With most heating systems sitting on the floor can be the coldest place making it uncomfortable with unfloor heating your heating the place its most needed, walking arround with no shoes on in winter in the house is great. Warm feet make you feel warmer than having a warmer house!

[Andeh13]

Thanks for the advice, unfortunately under floor heating would be difficult to install. The house has nice floors so I would struggle to justify replacing them, esp over the costs involved on top of replacing the warm air system as well.

Everything is gas fired here, so not looking into electric systems. Had one of those in my last year of university & hated it!

[oolon]

Thanks for the advice, unfortunately under floor heating would be difficult to install. The house has nice floors so I would struggle to justify replacing them, esp over the costs involved on top of replacing the warm air system as well.

You do not have to use the same system is every room. We are hopping to complete on a new house soon and one of the things we wish to do is to replace the kitchen, underfloor heating in that room would be very good as cooking at produce a lot of heat itself and we are already messing up the room big time. However I will not be pulling up the wood block flooring in the living room for underfoor heating. However will consider it for the bath room along with a heated towel rail. Air would be perfect for my study (too many computers) as its always too hot and it would be great if the air was taken away and used elsewhere in the house.

[Sputnik]

Personally I like the conventional type of central heating with a condensing boiler, You can use normal radiators, Underfloor heating grid or those skirtingboards that act as non-conventional radiators and it will provide you with hot water at a large enough quantity to use it for a decent shower mixer too.

I've never been a fan of the hot air systems.

[scaryjim]

Yes, you're thinking of a combi boiler, where the boiler provides hot water on demand. tbh, I don't think they're that good (although combi boilers have come a long way in the last 10 - 15 years in terms of the flowrate they can provide on hot water) and would prefer a tank, but modern combi boilers are generally pretty good. If you can use condensing boilers for warm air systems, I see no reason you couldn't use a condensing combi, but I don't have any expertise in that particuar area - as above, Johnson and Starley seem to be the name that always comes up when these things are discussed online, so I'd have a look at their website and maybe give them a ring if you've got any questions...

[scaryjim]

Underfloor heating is a pain to retrofit to a house, frankly. If it doesn't have it already I wouldn't bother trying to put it in.

[oolon]

Rather than having a water tank you can get accumulator tanks (thermal stores) these do not use the hot water in them to supply the taps, the heating system heat the accumulator, that then feeds the raditators etc. This is good as it allows the heating system to remain on for a longer period of time before cutting out. The worst time to use the heating system is when it keeps switching on and off. An accuimulator heats up more than needed when the heating comes so when it reaches temperature the boiler will go off for alot longer. Plus you can connect solar to them.

here is an example of an accumulator

[Sputnik]

I was thinking a either a Condensing System boiler or a condensing combi boiler. Personally, I'm not a fan of Combi's either so I have a Condensing system boiler with a hot water cylinder.

Those hot air systems you linked to do look good.

[tiggerai]

Rather than having a water tank you can get accumulator tanks (thermal stores) these do not use the hot water in them to supply the taps, the heating system heat the accumulator, that then feeds the raditators etc. This is good as it allows the heating system to remain on for a longer period of time before cutting out. The worst time to use the heating system is when it keeps switching on and off. An accuimulator heats up more than needed when the heating comes so when it reaches temperature the boiler will go off for alot longer. Plus you can connect solar to them.

here is an example of an accumulator

I think this is what I've got (coming up to 4 years old) and I couldn't fault it. My boiler only needs to be on for about 10-15 mins for a shower and to make a considerable heat difference to the house.

Andehh - Make sure you're checking out if the Insulation in the house can be upgraded as this will also save considerable money and heating costs. No point putting in a new heating system if all you're doing is heating the street!

[Andeh13]

Thanks for all the replies guys, will check out the insulation in the house! Gunna try and get hold of Johnson & Stanley as well, they seem to keep coming up.

If anyone else has any experience or knowledge of them I'd be grateful!

[GoNz0]

learn to solder pipes like i did, then you can sort and pressure test your own rads saving about a grand and do whatever work needed to hide the pipes behind the skirting boards using the boards designed to take plumping pipes and wires. you then pay for the heating boiler to be fitted and the system commisioned.

i have saved thousands doing plumping and electrics. we had new heating from the last owner, but there were tits and put rads in the wrong places so i did a lot of soldering under the floors to reroute them under the windows.

[oolon]

i have saved thousands doing plumping and electrics. we had new heating from the last owner, but there were tits and put rads in the wrong places so i did a lot of soldering under the floors to reroute them under the windows.

Thats always an interesting question rads under the windows lose more of the heat as it can go out the window (less efficent), however rads on walls lose valuable wall space. This can be improved by fitting better energy efficent glass.