Energy Recovery Ventilation

erv image fro zenith r page

Zenith Remedial is the number 1 choice for ALL ERV Installations in Australia.

What is an HRV or ERV?

HRV or heat recovery ventilation or ERV, energy recovery ventilators are methods used to reduce traditional heating and cooling demands of buildings, both commercial and residential. An HRV system will exchange the indoor air that is stale with fresh air from outside. It also captures the heat from the air that it removes and transfers it to the air entering, preheating it before it comes into your home.

In a similar way, an ERV can also treat and precondition air from outside, pushing it through your home. In essence, what you’re doing is exchanging the air from inside to outside, but having it set and conditioned in a specific way that you want it done.

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Subfloor Ventilation

Ventilation is an important element of an energy-efficient home. Air sealing techniques can reduce air leakage to the point that contaminants with known health effects such as formaldehyde, volatile organic compounds and radon are sealed into the house. Ventilation also helps control moisture, which can lead to mould growth and structural damage. In a tight home, mechanical ventilation is necessary to achieve effective ventilation.

There are three basic ventilation strategies—natural ventilation, spot ventilation, and whole-house ventilation


Natural ventilation is the uncontrolled air movement in and out of the cracks and small holes in a home. In the past, this air leakage usually diluted air pollutants enough to maintain adequate indoor air quality. These days, we are sealing those cracks and holes to make our homes more energy-efficient, and after a home is properly air sealed, ventilation is necessary to maintain a healthy and comfortable indoor environment. Opening windows and doors also provides natural ventilation, but many people keep their homes closed up because they use central heating and cooling systems year-round.

Natural ventilation is unpredictable and uncontrollable—you can’t rely on it to ventilate a house uniformly. Natural ventilation depends on a home’s airtightness, outdoor temperatures, wind and other factors. During mild weather some homes may lack sufficient natural ventilation for pollutant removal. During windy or extreme weather a home that hasn’t been air sealed properly will be drafty, uncomfortable and expensive to heat and cool.


Spot ventilation can improve the effectiveness of natural and whole-house ventilation by removing indoor air pollution and/or moisture at its source. Spot ventilation includes the use of localised exhaust fans, such as those used above kitchen ranges and in bathrooms.


The decision to use whole-house ventilation is typically motivated by concerns that natural ventilation won’t provide adequate air quality, even with source control by spot ventilation. Whole-house ventilation systems provide controlled, uniform ventilation throughout a house. These systems use one or more fans and duct systems to exhaust stale air and/or supply fresh air to the house.

There are four types of systems:

Exhaust ventilation systems Work by depressurising the building and are relatively simple and inexpensive to install.
Supply ventilation systems Work by pressurising the building, and are also relatively simple and inexpensive to install.
Balanced ventilation systems, If properly designed and installed, neither pressurise nor depressurise a house. Rather they introduce and exhaust approximately equal quantities of fresh outside air and polluted inside air.
Energy recovery ventilation systems Provide controlled ventilation while minimising energy loss. They reduce the costs of heating ventilated air in the winter by transferring heat from the warm inside air being exhausted to the fresh (but cold) supply air. In the summer, the inside air cools the warmer supply air to reduce ventilation cooling costs.


Ventilation for cooling is the least expensive and most energy-efficient way to cool buildings. Ventilation works best when combined with techniques to avoid heat build-up in your home. In some climates, natural ventilation is sufficient to keep the house comfortable, although it usually needs to be supplemented with spot ventilation, ceiling fans, window fans, and—in larger homes—whole-house fans.

Ventilation is not an effective cooling strategy in hot, humid climates where temperature swings between day and night are small. In these climates, however, natural ventilation of your attic (often required by building codes) will help to reduce your use of air conditioning, and attic fans may also help keep cooling costs down.

Rising Damp and Health Issues

First of All, What Is Rising Damp?

Rising damp, a worldwide phenomenon, is a major cause of decay to masonry materials such as stone, brick and mortar. Even when mild it can cause unsightly crumbling of exterior masonry and staining of internal finishes. It may also cause musty smells in poorly ventilated rooms.

Rising damp occurs as a result of capillary suction of moisture from the ground into porous masonry building materials such as stone, brick, earth and mortar. The moisture evaporates from either face of the wall (inside or outside), allowing more to be drawn from below. The height to which the moisture will rise is determined by the evaporation rate and the nature of the wall. The normal limit for rising damp ranges from 0.5 to 1.5 metres above ground level.
Accurate diagnosis of the cause and extent of the damp problem is very important. Specialist advice should be sought.

Health-Related Issues caused by Rising Damp

Mould associated with damp buildings can trigger nasal congestion, sneezing, cough, wheeze, respiratory infections and worsen asthma and allergic conditions.
People who are more susceptible to these symptoms and other serious health effects include those with:
● weakened immune systems
● allergies
● severe asthma
● chronic, obstructive, or allergic lung diseases

According to the NSW Health Department

People with asthma, allergies, or other breathing conditions may be more sensitive to mould. People with weakened immune systems (such as people with HIV infection, cancer patients taking chemotherapy or people who have received an organ transplant) and with chronic lung diseases (such as Chronic Obstructive Pulmonary Disease (COPD) and emphysema) are more at risk of mould infection, particularly in their lungs. The NSW Health Department continue to state, Rising damp is ground moisture rising up a brick or stone wall. Poor subfloor ventilation or moisture in the subfloor area will worsen the problem. This can be fixed by installing a new damp course or waterproof barrier in the wall. Ensure the weep holes and air vents at the base of your home are uncovered.

If you have rising or lateral damp an experienced building consultant can check the ‘damp course’ and recommend ways to fix the problem.

For more information call 1300 314 113