HRV SYSTEMS
Blog post description.
8/26/20263 min read
HRV = Heat Recovery Ventilation. The main purpose of an HRV system is to bring fresh outdoor air in (via filter) and stale indoor air out. This is useful if your home suffers from condensation and dampness, because it will prevent mould growth. This is common in older Christchurch and Canterbury homes, especially those built prior to 1978 which is when NZ Insulation Standards were introduced. Poor insulation is still apparent in homes newer than this because those 1978 standards were the bare minimum compared with what they are today. This article will illustrate the main benefits to an HRV System.
MOISTURE CONTROL
Moisture and dampness builds in any home due to regular household activities like cooking, showering, drying clothes and even simply breathing. It is important that we have good airflow in houses so that mould does not form. Microscopic mould spores float around in the environment, and when an environment is damp this allows the mould spores to feed and grow. Mould growth is well known to cause health problems, particularly affecting more vulnerable groups such as infants, children, elderly and immunocompromised individuals. An HRV system will lower moisture across the home by effectively circulating air by bringing fresh air in and stale/damp air out. This means mould spores struggle to attach to surfaces in the home. Opening windows can help, but this is uncontrolled and inconsistent throughout the home, and will result in "dead" spots in the house where damp air can sit and mould can begin/continue to grow.
AIR QUALITY
An HRV system not only reduces the moisture/dampness in the air, but it also filters the outdoor air that comes in. The filter helps remove allergens like dust and pollen, as well as bugs from entering your home (unlike an open window). This effect is great in Canterbury because the Canterbury plains make this part of New Zealand very exposed. This flat, exposed area of land lacks physical barriers like hills and mountains, so when winds sweep across Christchurch (especially the North and Western suburbs) it carries lots of pollen and allergens with it. This can be particularly difficult during springtime for those that suffer from hayfever. illustrate the main benefits to an HRV System.
HEAT EXCHANGER
HRV systems also feature a heat exchanger. The principle behind this is that the heat energy between the fresh air entering and the stale air existing is exchanged. So overall there is no loss in temperature. The air itself does not mix but rather the heat transfers between the two air pathways. What this means:
In winter - the heat from the warm inside air transfers to the cool outdoor air entering, so your house does not become cold from the cool air outside. This means your heat pump (or other heating source) does not have to work extra hard to maintain warmth
In summer - the opposite occurs where the hot outside air will transfer its heat to the indoor air that is exiting the home. In turn this means your heat pump (or other cooling source) does not have to work extra hard to maintain a cool temperature
The overall stability of temperature is important for energy efficiency. This is because you do not have to heat/cool your room to maintain temperature with an HRV system thanks to the heat exchanger. Alternatively, whilst opening windows provides free and natural ventilation to some areas of your home, you lose temperature control. Then your heat pump which has high power consumption has to work hard to try offset the uncontrolled air that is coming in through the windows. This is wasteful when an HRV system running 24/7 has low power consumption.
COMPLEMENTARY WITH HEAT PUMP SYSTEM
If you wish to actively heat or cool your home, a heat pump system is required because an HRV does not change the temperature of your home/office, but rather maintains the existing temperature. These two systems differ, but complement each other very well. In an ideal world, both an HRV and heat pump system would be in place to ensure a dry, comfortable home/office.