Air to Air Heat Recovery Ventilation Systems
Over the years buildings have become more air tight due to better windows, doors, insulation and building systems. The air inside a house should be changed by ventilation which in the majority of houses is provided by opening windows and air vents in each room. The problem with these vents is that the warm air inside the house is blown or sucked out resulting in heat loss. One of the other problems is people sometimes block up these air vents to stop the heat loss and noise but this however creates new problems such as lack of ventilation, stagnant air, gas build up. The air to air Heat Recovery Ventilation (HRV) system changes all of this.
How the system works
The Heat Recovery Ventilation (HRV) sucks out the warm moist stale air from rooms such as the kitchen, bathroom and utility feeding it through a honeycomb of straws (a high efficiency counter-flow heat exchanger) and expelling it outside once the heat has been stored in the honeycomb. At the same time it brings in fresh cold air from outside. The cold air is heated up as it passes over the warmed honeycomb resulting in clean fresh warm air being pumped into the building. Some of these units are up to 93% efficient. The heat exchange unit is generally fitted in the attic and the air is transported through vents and ducting built into ceilings and studwork. The unit consumes a small amount of electricity to run a fan.
The system is fitted by specialised suppliers and installers and costs will depend on the size of the house and whether it is a new build or a retrofit. Fitting the system when the house is under construction is the best time but they can be retrofitted. A payback period of 7 to 10 years would be expected.
Some benefits of Heat Recovery Ventilation are:
- Clean fresh air
- Reduces build up of gases
- Reduces home heating costs
- Filters dust and pollen from the air
- Creates a good living environment
- Control condensation
- Closed windows and draught free ventilation
- Increases energy rating of building
- Reduces global warming
- Locked windows means a safer home
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