Heat Recovery Ventilation Options for Your Home

Copyright (c) 2015 Matt Reardon

Study results published in the International Journal of Ventilation, Volume 2 No. 3 of Dec 2003, have indicated that in climates that are colder, energy efficiency could be improved considerably by employing a heat recovery ventilation system. Results have indicated that a conventional exhaust system may use up to 67 per cent more energy compared to heat recovery ventilation (HRV) system.

How does HRV Work?

Even though an HRV could be quite effective during the summer season, it's most fashionable in climates which are colder during the winter. However, when the temperature dips below around minus 20° F, frost could build up within the exchange unit core. To deal with this, a damper shuts off the incoming cold airstream and then routes warmer air through the unit core. After a couple of minutes, a timer will open the port bringing in fresh-air and the ventilation continues.

A standard HRV for your residential use could shift as much as 200 cfm of internal air, although your fan speed could be set in accordance with the air quality in your home. For instance, a fan that is slow to medium speed might be sufficient for normal home living; whilst when your house is packed with guests it might need to be set at the highest setting. Ventilation speed controls are available for remote and intermittent operation.

HRVs are perfect for a home that is moisture-prone for the reason that they will replace the humid air in your home with fresh and dry air. In those climates having excessive humidity outdoors, an energy-recovery ventilator (ERV) system is more appropriate. The ERV is similar to your HRV, but in addition, it dehumidifies your incoming fresh airstream.

What are Ventilation Requirements in Australia?

All ventilation systems ought to be designed and installed in accordance with the Building Code of Australia, which should be followed together with Australian Standards 1668.1+2 dealing with mechanical ventilation systems.

Specifically, Australian Building Code Paragraph 3.8.5.0 stipulates that performance requirement is met for mechanical ventilation systems if they are installed in accordance with the provisions of Australian Standards1668.1 and 1668.2. These two Standards deal with mechanical ventilation for tolerable indoor air quality.

According to the CIBSE Journal Feb 2013 issue, the reduction of energy usage in homes and buildings is not just an economic issue. It is also increasingly being linked with opportunities of lessening the demand being put on the primary source of energy and the networks of distribution, as well as lessening life cycle environmental effect.

Which Option is the Most Efficient?

Of course, it could be said that the most efficient option would be natural ventilation, usually through your windows which can be easily opened.

In general however, individual fans with no ducting are possibly the most efficient among the available mechanical ventilation alternatives. So long as your ducting, intake and discharge are realistically sized, individual ducted fans may not be too bad either. Preferably, from a cooling and heating perspective, your fans ought to have automatic shutters or dampers so that there is no leakage of air them when they are not running.

A fan coming with some kind of operation control like manual on/off or one that is interlocked to your light switch is going to be significantly more efficient than a fan which continuously on.


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Matt Reardon is a well trained machine and systems operator. His services at MouldBuster include explaining to you all the available ventilation options. By the time you leave Mould Buster, you would have the best ventilation system possible. To view all the services and systems they produced see our page at http://mouldbuster.com.au .