Nowadays, when building a house, we focus on making it energy-efficient, meaning, above all, airtight (so that our accumulated heat doesn't escape). Unfortunately, gravity ventilation doesn't guarantee this. It relies on air exchange through gaps in the house. In the case of an energy-efficient house, there are practically no gaps. When building an energy-efficient house, heat recovery is a must! Thanks to it, we have ventilation without losing heat.
What is a heat recovery unit and what is it used for?
A heat recovery unit is a ventilation device with heat recovery that recovers energy from the exhaust air of a building and transfers it to the supply air. This allows for air exchange while reducing heat loss, which translates into heating savings. Heat recovery involves mechanically exchanging stale air with fresh, purified air from outside. During this process, heat is recovered from the air drawn in from the house.
Functions of a heat recovery unit
- Air exchange: removes stale, polluted air from rooms and supplies fresh, filtered air from outside.
- Heat recovery: transfers heat from exhaust air to supply air, minimizing heat loss and reducing heating costs.
- Improving air quality: filters the air, removing dust, pollen, and other pollutants.
- Maintaining thermal comfort: ensures a constant temperature in rooms, regardless of external conditions.
How does heat recovery work?
The heart of a heat recovery system is the ventilation unit, or heat recovery unit. It extracts air from two directions simultaneously – from the outside and from the house. These streams meet in the heat recovery unit, or more precisely, the heat exchanger. The streams do not mix, as each flows through a separate duct. Air drawn from the house passes through the heat exchanger, where it releases its heat, while air supplied from outside absorbs this heat back. Finally, the cleaned and warmed air is distributed through ventilation ducts throughout the house, and the dirty air is expelled outside.
Another advantage of heat recovery is that it rids the air of all allergens, making it suitable for allergy sufferers. To sum up – the happy owner of a heat recovery unit can enjoy purified air in their home without losing heat!
Construction and operation of a heat recovery unit
A heat recovery unit is a ventilation unit with a heat exchanger, supply and exhaust fans, filters, and controls.
- Heat exchanger: Recovers heat from exhaust air and transfers it to the supply air.
- Fans: Ensure air movement in the ventilation system.
- Filters: Clean the air of contaminants.
- Control elements: Allow for the adjustment of operating parameters recuperator.
The ventilation system consists of an air intake, an exhaust vent, a supply air intake, and an exhaust vent. The intake vent draws in fresh air from outside and introduces it into the heat exchanger in the recuperator. The exhaust vent draws in air from inside and introduces it into the exchanger through a separate duct. Heat transfer occurs in the exchanger. The air from inside the house transfers heat to the air drawn in from outside. Then, after the heat is transferred, the used air is exhausted outside through an exhaust vent, while the fresh, warmed air is distributed throughout the house.
Benefits of heat recovery
- Heating savings: Thanks to heat recovery, heating costs can be reduced by up to 30-50%.
- Improved comfort: Constant, controlled air exchange ensures fresh and clean air indoors.
- Heater home climate: Eliminates moisture and prevents the growth of fungi and mold.
- Environmental protection: Reduces energy consumption, which has a positive impact on the environment.
Mechanical vs. Gravity Ventilation
The difference between mechanical and gravity ventilation is that mechanical ventilation not only ventilates the room but also cleans it of pollutants and recovers heat from previously used air.
Gravity ventilation draws air out of the house, losing its heat. At the same time, it draws in air from outside (introducing it through leaks in the house, such as cracks in windows and doors, and ventilation grilles), which is cold (in winter) and uncleaned.
Heat Recirculation – When to Install?
It's best to start thinking about heat recovery during the construction phase of the house. If you decide to install heat recovery in a house that's already built, it will involve higher costs due to the work, which will simply take longer. At the time of construction, all you need to do is install the system. You don't need a heat recovery unit yet. First, simply install the appropriate ducts and secure the area where the unit will be installed.
Advantages of heat recovery
Heat recovery increases living comfort, protects our health, and saves us energy. However, it also offers additional benefits, such as:
- filters the air from pollen, which is beneficial for allergy sufferers;
- cleans the air from smoke and vehicle exhaust;
- gives us full control over the amount of air supplied and exhausted;
- removes moisture, resulting in fog-free bathroom mirrors;
- quickly removes odors, such as those from cooking food in the kitchen;
- reduces the amount of dust in the home, reducing the number of viruses, bacteria, and dust mites;
- Because you don't have to open windows, the number of insects in the house is reduced, and street noise doesn't bother you as much;
- In a house with heat recovery ventilation, laundry dries faster, and floors dry faster after washing;
- Installations can be expanded with an air heating and cooling system (however, this doesn't offer the same capabilities as, for example, air conditioning);
- Mechanical ventilation can be fully automatic, thanks to CO2 and humidity sensors;
- It can be connected to smart home systems;
- It increases the value and standard of the house.
Is heat recovery necessary?
Ventilation in the house is essential. You can choose between gravity and mechanical ventilation. We've already mentioned the disadvantages of gravity ventilation, as well as the advantages of mechanical ventilation. Energy savings, comfort, and health benefits resulting from having a heat recovery system give us the confidence that investing in heat recovery is worth it (the costs of which are comparable to mechanical ventilation).