The first-ever passive house by Koskisen was completed in Hyvinkää last July. Herrala Houses’ Kaukovaara model turned out to fulfil the occupants’ every wish.
More accurate information on the energy consumption of Mike Holopainen’s and Maija Puronvarsi’s passive house will not be available until after the winter.
“The house was fitted with an energy meter at the end of January. In the spring we will find out how much of the electricity we consume is used for water heating, for the underfloor heating of the wet rooms, for radiators and for household appliances,” Mike explains.
To heat the main level, with its 44 centimetre thick walls, in the wintertime, Mike and Maija mainly use a heat-retaining fireplace, which they fire up two or three times a week.
“The radiators on both floors have been set to emit constant low heat, but I can’t say if they have consumed more or less energy compared to a regular electrically heated house. We will know more after we get the figures from the energy meter,” Mike ponders.
On the whole, Mike and Maija are very pleased with their new home.
“The floor solution seems functional, and many of our visitors have admired the spacious kitchen. Herrala Houses’ designers have done a good job with this model,” Mike compliments.
Mike and Maija would not think twice about building another passive house.
“In terms of insulation, for instance, we would know how to choose more cost-efficient solutions the second time around. We could improve some other minor things too, but I am sure anyone who has built their first house would say the same,” Mike points out.
According to Herrala Houses’ Development Engineer Janne Inkinen, the house factory received a lot of valuable information from Mike’s and Maija’s project for the future. The follow-up on the house continues, since Inkinen has installed sensors inside the exterior walls in order to monitor temperature and moisture within the wall structure.
“The results show that the wall structure and especially the wind barrier wool, installed on top of the wind barrier panels, have functioned as planned. The structure remains dry.”
The house factory has made use of the experience, for example in the spacing of a passive house’s frame posts.
“We will prioritise sheet insulation in the spacing of the exterior wall posts as far possible in order to maximize the insulation in the wall and so that the post spacing can better accommodate the standard insulation sheet size. Window and door openings and other similar structures normally create irregularities in the spacing of posts, and you have to cut the insulation sheets to fit them in-between the posts. Cutting the insulation sheets is laborious, particularly in a passive house, which has a lot of insulation.”
According to Janne, Herrala Houses will most likely start its next passive house project next summer.
Commissioned by: Mike Holopainen and Maija Puronvarsi.
Prefabricated house supplier: Koskisen Oy, Herrala Houses
Model: Kaukovaara, adapted
Designer: Koskisen Oy / Tytti Mäntyoja
Building contractor: Mäntsälän Laatutalot Oy
Lot size: 990 m²
Net floor area: 190 m²
Gross floor area: 223 m² + unheated warehouse/car shelter 22 m²
Frame: Wood, pre cut
Heating system: Space heating, underfloor heating in wet rooms and entrance hall, other rooms equipped with radiators and individual adjustment + heat-retaining fireplace
Ventilation: Forced ventilation, heat recovery system, earth cooling tubes