Heat Recovery Ventilation System | Heat Recovery Unit

Greenworks is a brand partner of

Heat recovery ventilation systems work by both supplying and extracting air throughout your home, 24 hours a day, 7 days a week to give continuously good air quality.

Air is extracted continuously from the wet rooms in the house (I.e. the kitchen and bathrooms). This air passes into the ventilation device and over the heat exchanger unit, which can recover up to 93% of the heat in the air that would otherwise be lost.

At the same time, air is continuously drawn in from the atmosphere and ducted to habitable rooms (living rooms and bedrooms) to provide a balanced ventilation system.

WHAT ARE THE BENEFITS?

These products can reduce the CO2 emissions of a dwelling by 'salvaging' and re-introducing heat into the property which would otherwise have been exhausted if you were using a conventional system without heat recovery. This energy saving contributes to a reduced DER (Dwelling Emission Rate) in SAP.

Heat recovery uses just a few Watts of energy (<1W/l/s) to recovery many kiloWatts of otherwise lost heat from buildings through conventional ventilation. This means lower fuel bills and carbon emissions.

It also ensures less damage to the building structure from condensation and mould which would otherwise build up on today's air-tight homes.

An often undersold, but to those who have the system important, benefit is the delivery of fresh oxygenated air directly to living areas which increases cognitive performance and eases sleep.

HOW DOES IT WORK?

A whole house heat recovery ventilation unit is designed to run 24 hours a day, seven days a week to give continuously good air quality for today's air tight homes.

As part of the 2010 Building Regulations Approved Document L consultation workshop, it was pointed out that modern buildings can lose up to 25% of heat due to uncontrolled ventilation and air leakage. Heat recovery appliances can recover more than 90% of this heat.

A central heat recovery system will take air from the bathroom, kitchen, toilet and utility (wet/smelly) rooms and feed it through duct into the Heat Recovery unit before passing it to outside. Fresh air is drawn from outside to the heat recovery unit before distributing through another duct system to living and bed rooms.

Heat exchange takes place within the appliance by blowing the outgoing stale but warm air through adjoining channels to the incoming fresh cooler air which is blown in the opposite direction.

In line with the second law of thermodynamics, heat will move from the hotter region to the colder region of the heat exchange system.

WHERE CAN THEY BE USED?

Almost any domestic building could benefit from heat recovery installation. Draughty buildings will need to have the draughts isolated before installation. Buildings with open flue appliances have to be ventilated separately and therefore central ventilation has to be considered carefully in these scenarios. Products are 'sized' according to a property's floor area and the ducting lengths required to ensure that the unit specified is as efficient and effective as possible.

INSTALLING A HEAT RECOVERY SYSTEM?

Units can be fitted in eye-Level kitchen cupboards or lofts and can be simply installed and plugged in with a three pin plug. Loft units which are too big to go through the loft trap have to be dismantled or installed before the ceilings.

Duct is then run to the rooms; There are a number of plastic duct profiles which all interlink to enable almost any installation. To reach lower floors, duct can be boxed into corners of upstairs rooms, fitted wardrobes or run within the stud walls themselves.