We offer the Daikin range of Heat recovery (HRV).   The Daikin HRV can be a stand alone system or used as an add on to a high velocity system. There are models ranging from 150m3/hr to 2000 m3/hr.  

As homes are constructed to better standards with less and less infiltration, the necessity to ensure that a known amount of fresh air is brought into a building has increased.  This can be achieved by using a HRV.

Up to recently in Ireland, the focus was on insulation with no regard for infiltration.  Infiltration is the uncontrolled movement of air in and out of  a building or "air leakage".  Traditionally, you would put the best insulation in a building and then leave a 150mm diameter hole in the wall of each room.  The only problem with this is that when it is windy, the heat that was in your building would be displaced by cool air coming in through these "trickle vents"  

This logic of "trickle vents" predates heat recovery (HRV), ICF construction, timber frame, SIPS and other forms of construction in Ireland.  When looking at the amount of heat needed for a building, the building structure accounts for 30 to 45% of the heat requirement.  The remaining 55 to 70% is the heat required to heat the infiltration of the cold air that will enter and displace the warm air in your building.  In the US and Canada there is a maximum of .33 (one third air) infiltration rate, (also known as air changes per hour ACH).  In Ireland a well constructed house will have between 2 and 4 air changes per hour.  

How do you ensure that your building is air tight?  The best method of ensuring your building is air tight is by getting a blower door test done.  This is where a fan pressurises the building and forces air out through any leaks in the building shell.  Even a small 1mm gap by 10mm long can have an effect on the air change rate.  Getting the blower test done will identify the problem areas in the building shell that left unsealed will cause you to spend more on your heating bills year after year.

Remember that a concrete block is not air tight, the plaster on the inside of the walls is gives the wall its airtightness.  Anywhere the plaster is not done, for example between floor joists and at the bottom of the skirting boards, air will leak into your home displacing the heat.  Also, remember if you have an unsealed fireplace/chimney you will increase your air change rate by .2 to .5 for every unsealed fireplace /chimney you have.

What does all this information have to do with Heat Recovery?  Plenty.  To save money on your heating bill, your building needs to be as air tight as possible.  You must have the air tightness verified by a blower door test and report.  It is not the building component U values that are important, it is the airtightness of the building.  It is not putting in triple glazed windows, the increase in U value and energy saving is insignificant (approx. 1 to 2KW) compared to the savings you will get by making your building as airtight as possible.  In a 230 M2 home, the building shell loss is usually 7 to 8 KW and the infiltration at 2 air changes per hour is usually 7 to 9KW. Every air change per hour increase will add an additional 3.5 to 4.5KW to the heating requirement of the building with an increase in the running costs.

When you have an airtight building, a Heat Recovery Ventilator is a must.  The health benifits of a HRV in an airtight house far outweigh the electrical cost of running the HRV.  First make sure the air tightness taken care of, otherwise you are wasting your money.  Unfortunately on the Building Energy Assesment (BER) heat recovery has a negative impact on the energy rating the energr (electricity) consumed in moving the air in and out of the building is greater than the energy (heat) recovered.

Each HRV system design is unique to each building.  Email in you plans to info@ejfidgeon.com for a quotation on a HRV system