warm air replacement

[wolfman1]

Always a subject to get people going, i posted here a while ago whilst trying to decide what to do with the heating system in our house that we are buying, and have now bought, what i wanted to know was the cost of installing a modern wau, answer was around 2-3k, however if you want a good room sealed unit with a water heater forget those prices, yes i could have got a j and s high spec unit for around the 3k mark, but a modern unit which is room sealed (draws the air for combustion down the flue) and add a water heater you are talking 4k plus especially with the electronic filter system, so what have i decided? well i'm sticking with the warm air as i see no reason to replace with an inferior wet system, the only real issue i had with warm air was the dust problem, or perceived dust problem, i have had a test run with the old system (39yrs old and still working) i cant say i noticed a dust issue, although i can see that the ducting could do with a clean, which i will do.

 

[Boilerman2]

I think you will be shocked by your Gas Bills next winter, I would never describe a wet system as inferior, on balance a wet system is best every time, the main problem with WAU's is that when they reach temp and shut down, the fan cools the Heat Exch and then stops, SUDDENLY the house feels COLD! so you end up with room stat set a 25'c which uses Loads of gas but hey what do I know, iv'e only been listening to customers complaints about WAU's for the last thiry odd years

 

[Deleted member 105431]

I think you will be shocked by your Gas Bills next winter, I would never describe a wet system as inferior, on balance a wet system is best every time, the main problem with WAU's is that when they reach temp and shut down, the fan cools the Heat Exch and then stops, SUDDENLY the house feels COLD! so you end up with room stat set a 25'c which uses Loads of gas but hey what do I know, iv'e only been listening to customers complaints about WAU's for the last thiry odd years

I've tried telling him but he knows best. . . .

 

[mickyg]

you can have a good modern warm air system, but to do it right and make it on par with a wet system in terms of controlability and efficiency would cost serious bucks, which tends only to be justifiable in the commercial sector where it is more popular. If you really like the warm air, you can buy a water to air heat exchanger run from a wet boiler.

 

[Boilerman2]

And wait until the WAU needs Servicing, there arn't many RGI's who bother taking ACS HTR1 now, people in my area are finding WAU's really difficult to get serviced

 

[Agile]

We all tried to warn Mr Wolf against warm air and to be fair he ( mostly ) listened but he seems to have reached the wrong decision.

There is no point in repeating all the pages of good advice we gave him but I will repeat the main disadvantages-

Dust particles

Noise transfer from room to room

Inability to control individual room temperatures easily

Wider short term fluctuations in room air temperature, particularly at startup

Tony Glazier

 

[simond]

I suggest Mr Wolfman looks at the new Lennox G61MPVT unit.

It's 94% EFFICIENT and is a gas condensing warm air unit. Upflow or downflow.

And it can be fitted with aircon.

Try that with your radiators.

 

[GeorgeBramwell]

I think you will be shocked by your Gas Bills next winter, I would never describe a wet system as inferior, on balance a wet system is best every time, the main problem with WAU's is that when they reach temp and shut down, the fan cools the Heat Exch and then stops, SUDDENLY the house feels COLD! so you end up with room stat set a 25'c which uses Loads of gas but hey what do I know, iv'e only been listening to customers complaints about WAU's for the last thiry odd years

This is incorrect. Modern Warm air units modulate the fans and burners. It is clear your exposure to this superior form of heating limited.

 

[GeorgeBramwell]

you can have a good modern warm air system, but to do it right and make it on par with a wet system in terms of controlability and efficiency would cost serious bucks, which tends only to be justifiable in the commercial sector where it is more popular. If you really like the warm air, you can buy a water to air heat exchanger run from a wet boiler.

I recall some companies were making slot in copper wet heat exchangers for retrofit. They would slot into a J&S unit. A combi then can heat the WAU and do the DHW as well. Anyone have any details, as it was while ago I last saw one?

 

[GeorgeBramwell]

I suggest Mr Wolfman looks at the new Lennox G61MPVT unit.

It's 94% EFFICIENT and is a gas condensing warm air unit. Upflow or downflow.

And it can be fitted with aircon.

Try that with your radiators.

I am impressed with that unit. Lennox make some decent stuff.

 

[wolfman1]

I think you will be shocked by your Gas Bills next winter, I would never describe a wet system as inferior, on balance a wet system is best every time, the main problem with WAU's is that when they reach temp and shut down, the fan cools the Heat Exch and then stops, SUDDENLY the house feels COLD! so you end up with room stat set a 25'c which uses Loads of gas but hey what do I know, iv'e only been listening to customers complaints about WAU's for the last thirty odd years

Modern systems modulate fan and burner and a cold house is more to do with the insulation not the heating system, i am led to believe that a warm air system is more efficient than a wet system (less losses due to heating the air rather than water then air) but i'll happily be proved wrong, our old house was a solid wall affair with a wet system which was rubbish at heating the house unless turned up and left on 24-7 so we topped it up with a solid fuel burner. so it will be interesting to compare a house that is 30% bigger, although i feel it is well insulated (kept cool in the hot weather) it is a chalet bungalow around 1500sq ft. so how much to heat (and hot water)? My biggest heating worry will be the conservatory we're having built, any good ideas on this, i thought a couple of heat pumps? any one got any experience with these? practical living with experience rather than anything else, are they really very efficient as suggested, does it not cost alot to run the compressors? Any other heating ideas? it is a large conservatory (30sq meters).

 

[Agile]

Radiators heating a room are 100% efficient. Any difference in efficiency will be in the WAU as compared with a wet condensing boiler which are all over 90% now. A good WAU would probably be of similar or less efficiency.

Heat pumps rarely show any advantage if a gas supply is available and have a very high capital cost and a very short warrantee.

Conservatories are not expected to be used during cold weather if they do not meet the full building regulations and there are usually limits on the heating system which can be compliently installed.

Tony

 

[David937]

I've been to a few commercial buildings were they have an air handling unit fed by the boiler, it is nice and comfortable and the system is never exactly off, once rooms are up to temperature the valves will not be 100% open and the system will be ticking over.....how much do you think this kind of system would cost in a home?

 

[GeorgeBramwell]

Radiators heating a room are 100% efficient.

They are? What do you mean?

A warm air system can heat a conservatory. Thermostatically controlled registers are available. They open and close to the wall stat.

 

[simond]

I would suggest you look at the Worcester Bosch air/air heatpump for the conservatory.

It is not easy extending an existing warm air system in most situations.

The air/air heatpump is at least as economical as a gas wet system for this application and has the ability of providing air cooling in the summer built in.

We have a couple of customers who've had these air/air units installed by us this year and the feedback has been brilliant.