Ventilation and Heat Recovery Systems
We are still preparing our range of ventilation supplies. Those links on the left which are currently 'ghosted' will be available shortly.
Why
ventilation is important
Heat Recovery (HR)- how it works
How much money will a HR systems save?
What about heating and cooling?
Find out how to go about having a Heat Recovery
system
Download our Ventillation brochure
You may think that a central vacuum system is a luxury, and you can put up with the inconvenience of an ordinary vacuum cleaner which, after all, 75% of the population (I'm including children here!) never come across because the other 25% do the housework and cleaning, but you must think again about ventilation.
Modern houses are becoming more and more air tight. Not only to stop draughts and save money on heating bills but because government building regulations demand it.
You want to seal up and insulate your house with double glazing, thick insulation and sealed windows and doors. This is eminently sensible economically and from a heat retention angle. But sealing and insulation come at another price.
You need oxygen in the form of fresh air in order to survive and stay healthy.
Not only that, the condensation formed from breathing, cooking and bathing creates the ideal conditions for the formation and growth of mould and survival of dust mites.
You must therefore ventilate your house.
Fit extractor fans in the kitchen, utility room, and bathrooms.
Suck all that warm stale air and moisture out of the house.
But - that air you blow out has got to be replaced with air from somewhere else – outside.
‘But we've just sealed up the house so no air can get in! Better make some holes somewhere in the form of air bricks or trickle vents above the windows to let the air in. Hang on a minute; it's cold outside and we've just paid a fortune for these double glazed windows and put 300mm loft insulation and now we're letting all this cold air in!'
It's not coming in the bedroom, because the curtains are drawn there. It's coming in somewhere else where there are no curtains and anyway the wind is blowing so one moment it's coming in one window and the next in another. It's not coming in the rooms where we want most air and coming in others which we are trying to keep warm.
Sorry, this is getting a bit out of hand but you get the point.
Suffice it to say that current building regulations insist only that you comply with the above scenario. Extract ventilators in the wet rooms and trickle ventilators above all the windows!
It really doesn't make a lot of sense when you are trying to save money and keep the house warm and help to save the environment by reducing your energy requirements.
This is where heat recovery comes in.
A heat recovery system consists of an extract vent (normally in the ceiling) in every wet room (kitchen, utility room, WC and bathroom) and a supply vent in every living room (lounge, dining room, bedrooms etc) and a heat recovery (HR) unit normally (but not necessarily) located in the loft.
Stale and moist air is extracted continuously from the wet rooms via the vents and is taken via ducting (80 to 150mm dia or equivalent cross section) to the HR unit. There, it passes through a heat exchanger (a bit like a car radiator) which is warmed up by the passage of this stale air.
Incoming air is passed over this same heat exchanger (there is no mixing of the outgoing and incoming air, this is what the heat exchanger is for), warmed by the latter and directed through ducts to each living room.
The amount of air, extracted from and supplied to the various rooms, is calculated to be the correct amount depending upon the type and size of room. The correct duct sizes and vents are fitted accordingly.
A heat recovery unit runs continuously, day and night and holidays. You switch it on and never switch it off.
HR units can be up to 95% efficient. This means that if you keep your house at a temperature of 22° C and the outside temperature is 2 deg C then the air coming in to your living rooms will be 21° C. This as opposed to 2° C through your trickle vents above the windows!
Installing an HR unit is the only way you can dispense with the installation of trickle vents in all your windows and still comply with building regulations. (BRE digest 398 refers. Page 4, Dwelling Characteristics, paragraph 3, final sentence).
How much money will a HR systems save?
That very much depends upon where you live, how warm you normally keep your house, how well sealed it is and other factors.
Payback time for a HR system is estimated to be between 3 and 12 years with the shorter payback being in the better sealed houses (e.g. Kingspan Tek House) Since the largest element of your energy bill is usually in heating, this is where you will see the greatest improvement.
Although you can have a cooker hood connected to the HR unit, these are currently units that do not fit well into modern kitchen designs. In addition a lot of steam and kitchen smells, NO2 and VOC's (volatile organic compounds) from gas are produced very locally, it is better for this to be removed locally at high speed intermittently rather than rely on the HR vent to remove it at a slower rate albeit continuously. Steam showers should have supplementary extraction. Drying machines should not be connected to the HR system and swimming pools should have their own dedicated specialist unit as should saunas.
What about heating and cooling?
Both heating and cooling can be added to the heat recovery system. The Neatafan HRD1 system includes a heat pump which provides an element of heating and cooling to keep your house at an even temperature in spring through to autumn. The efficiency of this unit particularly at low temperatures makes it more economical in heating mode than using gas. At 0° C outside temperature it provides the equivalent of 3 to 4Kw heating. You may therefore need additional heating depending upon the energy requirements of your house. This unit and the Artic.950 (sic) unit from Storkair which complements their MVHR.950 heat recovery unit will provide the equivalent of 2.2Kw of cooling. The extent to which they will cool the property depends very much upon its thermal efficiency and solar gain.
Find out how to go about having a Heat Recovery system.
(If you have constructive criticisms, corrections or suggestions to make in respect of the above statements please write to us at info@centralvacuums.co.uk)