Wolf Passive Homes

Technology

Future Building

Airtightness & Heat Recovery

MVHR or Air Handling Units (AHU)

5 year warranty
All products have been on the market for the past 25-30 years in Europe
Independently assessed by SP, Swedish National Testing Research Institute
Award winning technology, awarded by Swedish Energy Agency
Individual products or complete systems available 

Considerations

It is important to distinguish between the concepts of power demand and energy requirements.

Power Demand

This is a measure, which in this case is measured in watts, for example a 100W light bulb.

Example of Energy Required

What is the amount of energy that must be bought to the light bulb to light a lamp? For example, if the lamp is operated for 10 hours then you need to buy one kWh of electricity (0.1 kWh per hour going in that light is on). This is also true for a house.

If we ignore the hot water and household electricity, the distribution of house power demand is about 50% for the heating of ventilation air and 50% for heat loss through floors, walls, ceilings, windows, etc.

If the house is equipped with a balanced ventilation system, then the impact for the need for heating of ventilation air, is reduced by approximately 80%!

This obviously affects the energy requirement for the house each year. The house will consume a smaller amount of kWh regardless of what form of energy you choose (electricity, pellets, district heating, gas pump, etc)

We know with certainty that energy will not become cheaper in the future and the wisdom to take advantage when building a new house or changing the form of heating in your existing house, will pay dividends immediately.

A practical example: If you want to change your oil boiler to geothermal heat pump, you will not reduce the houses power needs. You will, however, reduce your need for purchased energy. Although you are no longer dependent on oil you now become dependent on electricity. You also know with certainty that electricity prices will rise and with them your costs.

Therefore, if you also change to a heat pump and install an AHU (air handling unit) and/or additional insulating the attic, you reduce the house power demand and hence the need for purchased energy forever.

General ventilation

The function of ventilation is primarily, to bring fresh air indoors. As a consequence, air should also be ventilated to remove harmful substances from the house. To make this work effectively means that the new air filter and the warmth of the old air, is recycled. (40% of heating needs in a modern house comes from the fresh cold air that is heated to room temperature).

Three types of solutions:

S - Self-Pull or Natural System

F - Exhaust Systems. A mechanical fan sucks the air out of the house.

FTX - Balanced systems. A fan that provides the house with fresh air and a fan that sucks out old air. Recovery of heat in the atmosphere is old to the new fresh air already in the air conditioner unit

Natural ventilation system

This principle is simple - hot air rises and is replaced by cold air from below. The cold air will enter through leaks at the joints between the floors, walls, windows, doors, roofs, etc. No real control of airflow. Air quality is not possible to maintain, nor heat recovery.

Exhaust System

Works much the same as a natural ventilation system with the difference that a fan could guarantee a minimum flow even during the warm season. Again, replacing the old air with cold outside air without any real ability to control or treat the incoming air.  In recent years, treatment controls in the form of valves have been tried but the maintenance required to maintain quality of the air, requires a major effort by the residents.

Balanced ventilation with Heat Recovery

This solution that provides control over the quantity and quality of the air and where it enters the home. This, together with a check on where and in what amount of old air is sucked out of the house creates a well-ventilated housing. A balanced system provides a dwelling with an oxygen-rich air environment, free from pollen and pollutants and a comfortable indoor climate with little temperature variation. In addition, the system works efficiently, making energy use minimal.

Purification of the incoming air removes pollen and particles easily collected in a filter (compared with the dust bag of vacuum cleaner). Noise from the system where rooms are interlinked by the same section of ducting, can be eliminated by using duct silencers.

A balanced ventilation system is now always provided with heat recovery. Heat recovery with an efficiency of 80% or higher are standard in new construction (efficiency indicates how much, in percentage, of the heat energy in the old air is reused to heat the new healthy air).

Heat recovery heats the cold air coming in, to room temperature. The temperature can be controlled and evenly maintained; making temperature variations within a room or apartment non-existent.

Large outdoor temperature fluctuations, such as spring and autumn, will have minimal impact on indoor temperature. High comfort, good indoor climate is the result. If you have an extra heat source, such as a fireplace, this helps the balanced ventilation system to distribute the heat throughout the house. Well-aligned steering and control systems allow for increased energy savings. All units have an integrated control system that is easy to use and adapt to your needs and wishes.

Source – Rec Indovent

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