Scandinavian Homes provide pre-manufactured low-energy Swedish timber-frame houses. The company, which is based in Galway operates all over the country. It was founded in 1991 and has built over 175 houses here since then.

Scandinavian Homes’ main emphasis is energy-efficiency. High levels of insulation in conjunction with ventilation heat-recovery systems and triple glazed low-emission-argon filled glass are important factors. The standard houses use only small amounts of energy for heating, while a 'passive house' option is also available. This is a standard where no heating is required for space-heating.

The company says its aim is to provide environmentally friendly houses - both for the occupants and for the environment in general. “To achieve this we use both simple natural materials and modern components taking advantage of the latest Swedish research on timber housing”, explains Lars Pettersson. Together with their customers, the company designs the house using its standard modular system. Mr Pettersson says they always strive to maximize the passive-solar heating through their triple glazed windows while taking into account the local wind, rain and other climatic conditions.

Large, open-plan designs, that give a luxurious feeling of space are easily achieved as the energy efficiency of the entire house makes such large areas possible to heat at all times.
Scandinavian Homes builds the highly insulated concrete foundation complete with under-floor heating and erects the insulated shell with roof, windows & doors. Other components such as water-saving taps, direct- pressure water-heater, ventilation heat-recovery system and timber floors are also usually supplied. Check out the company’s website to find out what is included in a ‘Scandinavian Home’.

Most customers prefer a timber exterior. In some locations it may be desirable to choose a plastered exterior option. This means that the external timber panel is replaced with a fibre-cement board. This solution is said to work as well as the timber cladding, but the wall looks like a conventional plastered wall.

Ventilation - Heat - Recovery system
The company places a lot of emphasis on a good ventilation system and high indoor air quality. A poorly insulated house is usually not very airtight which means that there is plenty of ventilation through the fabric of the building. Nowadays, however, in seeking to prevent heat-losses, houses are becoming more airtight and a new set of problems is created. A healthy indoor environment depends largely on removal of contaminated air and an ample supply of fresh air.

Scandinavian homes ltd. say that there are many problems associated with poor air quality: such as headaches, tiredness and allergies. They say that static/stuffy air is replaced with fresh air with many associated health benefits. In addition they say your home will be easier and less expensive to heat.

The seemingly conflicting imperatives of energy preservation and ventilation must be balanced in energy-efficient house designs. Rather than exclude fresh air, the Scandinavian Homes’ strategy is to exercise as much control over the movement of air to and from the building as possible, and to recapture heat from stale air before it leaves the interior.

Balanced ventilation system with heat-recovery
In a modern, airtight house, fan-assisted ventilation is needed to maintain required air changes and indoor air quality. When the sole concern is fresh air, simple fans may be used to exhaust stale air with fresh air entering through controllable slots in external walls. However the higher the price of energy the more economically attractive the idea of heat recovery. A balanced ventilation system with a simple air-to-air heat exchange is a good choice. The exchange of air is controlled and uniform throughout the year.

The energy benefit is that a dryer house takes less to heat, and that a higher degree of comfort is achieved at a lower temperature when the moisture level is lower. The fact that the fresh ventilated air is preheated in the heat exchanger at no cost is the obvious benefit. This is especially significant in tight highly insulated houses.

Installation consist of extraction points in “dirty rooms” such as kitchen, bathroom and laundry. Fresh air is distributed to all other rooms. The airflow is directed from clean to less clean rooms.
This system is operating with air only. It is not in any way connected to the water system. It is designed to be left on day and night, year round. It is not a heating system. This system will however help to indirectly distribute heat within the house. A solid fuel stove in the living-room can thus indirectly heat all the rooms in a house provided that the house is insulated well enough.

Balanced ventilation
system with heat-recovery and air-heat
Here, the total heat requirement of the house is taken care of by the ventilation system. Heating and ventilation is performed by one single system. The old air leaving the building is preheating the cold fresh air in the air to air heat exchanger. If air heating is to be the sole form of heat a duct heater needs to be added to the supply-air duct. This can be electrical or a coil for water heated by a central heating system. If a lot of heat needs to be added to the incoming air to heat the house, the air can feel dry and uncomfortable at times. This is why it is generally used only in passive houses which need practically no heat at all.

Heat exchanger construction
The Temovex heat exchanger is equipped with heat exchanger of the cross-flow type made of aluminium plates. Two adjacent plates form a narrow duct for either supply or exhaust air. The supply air passes through on one side of the plate and the exhaust air on the other. The heat in the exhaust air is transferred to the supply air via the plate. When the exhaust air condenses, the heat effect increases on the supply air side. The condensed water on the exhaust side can freeze if the temperature drops to under -10°C, but this is not really of any concern here in Ireland.

The design of the heat-exchanger allows no inter-leakage between the different media. For this reason, odours, bacteria and radon daughters in the exhaust air cannot contaminate the supply air.

The exchanger has very large surface to give a high efficiency grade of 82%

The above is just a small amount of information about Scandinavian Homes. There are many other noteworthy features (underfloor heating, etc.) to these homes that we will examine in our next issue.
Thanks to Lars Pettersson for his kind assistance.