Air central heating?

[Alisha]

Hi,

My partner and me are going to buy a house, and one of the ones we like has central heating by air (there are small grilles either on the floor or walls in every room). It's the first time we've seen this, as the normal thing is radiators, and we don't know if it works ok or it can have some kind of problem.

Anyone can give me some advice about this system? Is it better or worse than radiators?

Many thanks!

 

[BigBurner]

Hi,

My partner and me are going to buy a house, and one of the ones we like has central heating by air (there are small grilles either on the floor or walls in every room). It's the first time we've seen this, as the normal thing is radiators, and we don't know if it works ok or it can have some kind of problem.

Anyone can give me some advice about this system? Is it better or worse than radiators?

Many thanks!

If well designed and installed they are superior to radiators. It would not put me off buy the house. You can always add electrostatic air filters and heat recovery units later.

They heat up fast and are cheaper to run. They also cool in the summer by moving air around.

 

[mickyg]

Whilst warm air can be an effective form of heating there is a downside.
most warm air units around now are knocking on a bit. They were popular with new builds from the late 70s through to the early 90s. If the property is between 10-30 yrs old, its likely the unit will be the same age. You then firstly have potential problems with obtaining spares. There's also the issue of safety. I've seen more wau's than i would like with split heat exchangers, which causes products of combustion to circulate in the property, so a CO detector is an absolute must. The older ones are usually open flued and throw plenty of heat up the flue, which doesn't make them very efficient.
Some people like warm air, but personally I prefer wet heating, and I don't think there will be many of these tin cans knocking around in 20yrs from now.

On the plus side, they can be very reliable, sometimes lasting 30yrs+ , and they do heat the home quite quickly.

 

[BigBurner]

spare parts are freely available. Johnson & Starley bought out all makers and parts for 40 year old units are still available.

They becoming quite popular especially in larger properties as they can incorporate heat recovery and ventilation and humidification.

Some wet to air heat exchangers (air handling units) are available that can fit in place of the warm air unit if it needs replacing, heated by a boiler. Many use large combi boilers to heat the as these provide DHW too. They provide comfort cooling too.

Motorised dampers can be fitted to create zoning.

Give me a twin duct forced air heat recovery and ventilation system any day. Beats the hell out of radiators.

 

[Agile]

The downside is that many people find that the dryness of the air and the fine dust particles being circulated bring on asthma and similar respiratory problems.

It also circulates bad odours through all the house!

Tony

 

[Onetap]

The downside is that many people find that the dryness of the air and the fine dust particles being circulated bring on asthma and similar respiratory problems.

Tony

Not necessarily, but usually true.

Air leaks into/infiltrates buildings continuously, due to wind pressure and convection, carrying dust with it. A positive pressure system could supply filtered air at a positive pressure so that air mostly leaks out. A survey , by 'Which?' ISTR, some years ago found that the savings in cleaning costs could be a major factor in the payback of heat recovery ventilation systems. For example most car ventilation systems now have pollen filters.

WRT humidity, any heating system will generate dry air, with low Rh, in winter. You are relying on the latent heat gains (cooking, washing, laundry, breathing, etc) to maintain comfortable conditions. A system with a humidifier can maintain a steady Rh (and stop wood floors warping) but humidifiers are usually a maintenance nightmare.

The best system would be UFH with properly designed ventilation.

In reality, most warm air systems were installed by speculative builders, because they were the cheapest heating system and they are rarely maintained properly. Generally they do cause problems by stirring up dust and lowering the humidity.

 

[simond]

If the house you are looking at has a Johnson & Starley unit, and it is less than 15 yrs old, it should have some life left in it and spares should be obtainable.

Even better if it is an J&S Economaire which is room sealed, or a 'Modairflow or ET ' unit which has variable fan and gas valve for enhanced comfort.

We are still fitting warm air units, modern replacements are nearly always relatively easy to install. You can even have internal water heaters and unvented cylinders.

If the house is the one you want, i wouldn't be put off by warm air. Tescos, and probably your workplace will have similar air heating.

Edit: having read another post here, I should point out that if you have a Lennox, McClarey, Suggs, Halcyon, warm air unit, most spares aren't available.

 

[BigBurner]

Air leaks into/infiltrates buildings continuously, due to wind pressure and convection, carrying dust with it. A positive pressure system could supply filtered air at a positive pressure so that air mostly leaks out. A survey , by 'Which?' ISTR, some years ago found that the savings in cleaning costs could be a major factor in the payback of heat recovery ventilation systems. For example most car ventilation systems now have pollen filters.

Electrostatic air filters are easy to clean.

WRT humidity, any heating system will generate dry air, with low Rh, in winter. You are relying on the latent heat gains (cooking, washing, laundry, breathing, etc) to maintain comfortable conditions. A system with a humidifier can maintain a steady Rh (and stop wood floors warping) but humidifiers are usually a maintenance nightmare.

An in-duct humidifier can be a simple spinner.

The best system would be UFH with properly designed ventilation.

The best is forced air with heat recovery and ventilation. By a mile.

In reality, most warm air systems were installed by speculative builders, because they were the cheapest heating system and they are rarely maintained properly. Generally they do cause problems by stirring up dust and lowering the humidity.

A new J&S unit with an electrostatic air filter, modulating burner and fan with upgraded grills, will totally transform a system.

 

[stem]

I hated my WAU with a passion. OK, as BigBurner says the sophisticated properly designed ones with fresh air facilities, zoning and heat exchangers etc., are much better but cost huge sums to install. I would seriously doubt that's what you'll have.

I lived with my WAU for several years and will share with you my experience:

1. Warm air blown into bathroom, displaced the existing air. Where did this moist and erm.. stale bathroom air go? out of the bathroom door down the passage and back into the inlet duct of the system for re-distribution to all of the rest of the house. lovely!

2. Kitchen, as bathroom see above. Imagine the smell of cooking chips comming from the grilles in the bedrooms.

3. Poor comfort. Hot when the hot air was blowing on you directly, then instantly you felt cold the second the thermostat switched it off. A few minutes later a cold blast of air when it restarted before the hot air from the heater reached the grilles.

4. No zone control. Hot kitchen when cooking, thermostat in cool lounge kept the system running which pumped more hot air into the kitchen. OK I would sometimes manually close the kitchen grille, but then forget to open it again before I went to bed. It was impossible to get a comfortable temperature in every room. Lounge temp was OK'ish (other than 3 above) where the thermostat was, but other rooms that were too cold one day were too hot the next if the sun shone on them because the grilles didn't have any thermostatic control.

5. Noise transfer. Voices, TV etc travelled through the ducts from one room to another, especially in the bedrooms where the grilles were back to back. This didn't happen when the system was running as the noise of the fan & moving air drowned it out.

6. Mine melted a visitors pair of new boots (well the sole came off) which were left on the floor at the side of a outlet.

That enough for you?

 

[BigBurner]

I hated my WAU with a passion. OK, as BigBurner says the sophisticated properly designed ones with fresh air facilities, zoning and heat exchangers etc., are much better but cost huge sums to install.

You had a dog.

When the house is designed for it they are not expensive to install. As I said "Give me a twin duct forced air heat recovery and ventilation system any day. Beats the hell out of radiators."

They offer a hell of a lot - and not rads either.

 

[Onetap]

Electrostatic air filters are easy to clean.

An in-duct humidifier can be a simple spinner.

The best is forced air with heat recovery and ventilation. By a mile.

A new J&S unit with an electrostatic air filter, modulating burner and fan with upgraded grills, will totally transform a system.

You are Water Systems/Dr. Drivel and I claim the £5 prize.

 

[simond]

That particular prize was claimed weeks ago.

If you can shut him up its a tenner now.

 

[BigBurner]

Electrostatic air filters are easy to clean.

An in-duct humidifier can be a simple spinner.

The best is forced air with heat recovery and ventilation. By a mile.

A new J&S unit with an electrostatic air filter, modulating burner and fan with upgraded grills, will totally transform a system.

You are Water Systems/Dr. Drivel and I claim the £5 prize.

They seem popular men.

 

[gas4you]

How many have you fitted then BB to enable you to act as an expert on warm air systems?

 

[Agile]

Stem, as a genuine user of a WAU has given a well written description of their serious disadvantages.

DD, BB orwhatever he is calling himself today has only read manufacturer's spec sheets.

He has never lived with one himself otherwise he would know how bad they are!

BB is an armchair poster and has never installed anything in his life. Thats why he is not CORGI registered and not allowed inside the Combustion Chamber where genuine experienced people discuss things!

Tony