Ventilation and the Recovery of Heat
The requirement for managed ventilation in new homes grows as levels of insulation and air tightness are increased to improve energy efficiency. Architect Chris Morgan, writing for the Green Building Bible explains that damp, stale air needs to be collected and expelled from a house in order to avoid condensation and mould which can lead to sick building syndrome which in turn can result in allergies and asthma being developed.
Instead of expelling the damp, stale air outside as has been the convention in the UK, we can first recover the heat from the air and save considerable amounts of energy by using the recovered heat energy to heat water or fresh ventilation air.
The appropriate solution is dependent on the size of the property and how much air needs to be moved. It is advisable to look at the property's heating in conjunction with the ventilation needs as often these can be served by the same unit or combined in one solution.
On the one hand, a property built to passive house ('PassivHaus'*) standard doesn't really need any additional heating; heat from lighting, appliances and the occupants being enough to heat it. Heat recovery ventilation is, however, crucial. On the other hand, a new property built to current building standards needs both ventilation and heating.
*PassivHaus - This German term refers to a rigorously energy efficient standard for buildings where the building must not use more than 15kWh/m² per year in heating and cooling energy. In Sweden this figure is 10 kWh/m² per year.
Passive House Ventilation Solution
Ecoliving's Temovex solution is the heat recovery ventilation system maintaining a comfortable and healthy indoor climate in 95% of Sweden's homes built to the exacting PassivHaus standard. Temovex won the gold medal in the Swedish Energy Authority's prestigious competition to find the best heat exchanger for ventilation.
New Homes Ventilation Solution
New homes over 90 m² in floor area built to current building standards or better also benefit from the Temovex whole house ventilation system.
Ventilation, Heating & Hot Water
A ventilation solution for new homes of less than 90 m² in floor area built to current building standards or better is the NIBE Fighter 410P which pre-warms the supply air to living areas from the heat extracted and recovered from the wet rooms. A further advantage is that, using heat pump technology, the Fighter 410P also heats water for the wet heating system and for domestic hot water. Ventilation, heating and hot water are all delivered from the one unit the size of a tall fridge freezer.
Another alternative for new homes of less than 90 m² in floor area is the NIBE Fighter 360P which is also based on heat recovery ventilation and delivers ventilation, heating and hot water but instead of fresh air being supplied through the heat pump as in the case of the Fighter 410P, it is supplied locally to each room via trickle vents in the windows or specially designed wall vents.
Heat Recovery Ventilation with a Ground Source Heat Pump
Where a NIBE ground source heat pump is used for heating a new home, a NIBE FLM heat recovery module can be combined to ventilate. The damp, stale air from the wet rooms is extracted and recovered to the FLM module (heat recovery ventilation) where the heat is recovered and used to pre-warm the antifreeze/water mix coming in from the ground. For every 1°C uplift of this temperature, the efficiency of the heat pump is improved by 4%. Fresh air is supplied locally to each room via trickle vents in the windows or wall vents.
These solutions are intended as a guide and Ecoliving looks at the specific detail of any project before proposing a solution. Heat and hot water demand as well as ventilation flow rates are all factors that have a bearing on the most appropriate solution for any project.
Energy saving legislation means our focus is on building air tight, highly insulated homes. Heat loss has been reduced but are we in danger of creating unhealthy, polluted living environments?
25 years ago in Sweden, the construction industry had to face up to the material and health costs of Sick Building Syndrome - the results of a move to well insulated houses. The Swedes' response was to develop whole house ventilation with heat recovery, literally a breath of fresh air for low energy homes.
Whole House Ventilation with Heat Recovery
How it works:
Ventilation is a basic requirements for living in a healthy house. Controlled domestic ventilation with heat recovery reuses the energy from the exhaust air. Not only that, the additional heat generated internally from lighting, people and domestic appliances is also utilised through heat recovery.
Recovering heat from the humid areas of the house to a heat pump maximises energy efficiency whilst ensuring poor, damp exhaust air is regularly replaced with fresh air, creating a warm and healthy indoor climate free of moisture and mould. This is now the de facto solution installed in 90% of new houses in Sweden.
With years of refinements, improved efficiencies and proven effectiveness in one of Europe's most demanding climates, the heat recovery units and heat pumps from leading Swedish manufacturers NIBE offer UK self-builders and housing professionals a ready-made solution.