Questions and answers

What does the energy efficiency of a house mean?

Energy efficiency means the effective use of heating energy in the building. Energy consumption is measured in relation to the building´s area or volume, either as kWh/square metre or kWh/cubic metre. An energy efficient house is one whose energy consumption is half or less of that of a standard building per year. A passive house, which is often an optimal solution in terms of energy efficiency during the life cycle of a building, consumes only quarter, or sometimes even fifth of a standard house. For example in southern Finland, a standard building consumes approximately 120 kWh/square metre - an energy efficient house therefore consumes 60 kWh/square metre and a passive house 20 kWh/m2 per year.

How much can I save in heating costs over time?

Energy prices will rise significantly in the future. This means that all improvements will contribute to future savings. The profitability of an investment in the upgrading of the property must be calculated on a case by case basis. Heating costs can easily be halved by improving the insulation of the building´s shell and by efficiently recovering heat from exhaust air. The Technical Research Centre of Finland (VTT) calculated that the savings can total 30,000–50,000 euros over 25 years. The VTT also estimated that the resale value of an energy efficient property will be 10–30 per cent higher than the value of a standard house.

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How much will the value of my property increase compared with other similar properties, if I build or refurbish according to the new regulations?

The more awareness there is about energy efficiency and the more energy prices rise, the more will property prices also be affected. It is certain that a low-energy house can be sold at a higher price than a similar standard house. The energy label will probably have the same impact on property prices as the energy label had on the prices of household appliances. It has been estimated that a low-energy house will resell at a price that is 10-30% higher than a price of a standard house.

What is the most cost-effective way of increasing energy efficiency in a residential home?

The thermal insulation and airtightness of the outer shell have the largest effect on the energy efficiency of a private residence. Depending on the circumstances, the most effective way is probably to improve the insulation of the roof, the walls and the floor, and to replace old windows.

Is it possible to save money by insulating an old house?

It depends on what your starting point is. Insulating the roof is an easy and inexpensive way to start. If you need to replace your old exterior cladding, it is a good idea to add insulation and improve the wind barrier. Sometimes it is worthwhile renovating some building components to a passive level.

How much should one invest in insulation or energy efficiency to make one´s property a low-energy one?

This is a case-by-case issue. In general, a low-energy house (with energy consumption as low as half of a standard house) will have construction costs that are around 3% - 5% higher than the total construction costs of a standard house. A passive house would need an extra investment of only 5-10%, as separate heating systems can be left out entirely.

Building a house is expensive. Why should one increase construction costs by choosing expensive energy efficient materials and solutions?

Low-energy houses (with energy consumption lower than half of a standard house) have been built e.g. in Finland for more than 10 years. Many of these houses have been assessed and measured for a long time. According to VTT, the 3–5% additional construction costs generally pay themselves back in 5 to 10 years in the form of energy savings. Add to this the increase in the value of the house, and you will see that it is a good investment. In terms of lifespan cost, passive building (with energy consumption of less than quarter of a standard house) represents optimal design.

Why is the energy label necessary?

The aim is to save energy and cut emissions. The energy label guides every owner of a building or an apartment to sort out the advantages and importance of energy efficiency. An energy efficient house consumes less energy, is economical to live in and increases the resale value of the house. Also the need of imported energy decreases and is affordable for the national economy. Energy label has to be showed when selling or renting the apartment or house.
Energy labelling of buildings is also one of the most important ways of achieving the objectives of the Kyoto climate agreement.

What happens if I do not follow the new regulations when constructing a new house or renovating a larger old building?

The authorities will not give a building permit or the building will not pass the final inspection without an energy certificate. It will also not be possible to sell or rent a house without the certificate.
Can I sell or rent my flat or house to my friend without an energy certificate?

Can I sell or rent my flat or house to my friend without an energy certificate?

According to the directive, the energy certificate must be presented to the buyer, together with an explanation of how the energy efficiency of the house can be economically improved. The procedure is somewhat unclear at this time, but probably the notary would not confirm the sale without the necessary papers.

When does the energy certificate become a requirement in EU Member States?

The directive was adopted at the beginning of 2006 and must be in full use by all EU Member States by 2009.

There is no heating system in a passive house. Is it possible to heat up the house before moving in?

At the final stage of the construction work, lights, underfloor heating, refrigeration devices and heat resistor in the incoming air shaft are in use. If the house is not warm enough without the inhabitants this thermostat controlled resistor will take care of the proper heating.

How does a Passive House keep warm if its inhabitants are absent for a month?

When going away for a longer period of time, the house’s ventilation is set at minimum to decrease heat consumption. Please see also the previous question.

Will the windows of a Passive House fog up if they are not on the same level with the inner wall? There is no radiator below the window.

Because of the good ventilation ability of a Passive House the temperature on the inner surface of the windows stays close to the room temperature and the indoor surface of the windows will not fog up. Instead, after a cold night, windows can fog up from the outside in the morning. When outdoors temperature rises, glass will not warm up as fast and damp may condense momentarily on the cold surface.

Can I have large ”picture windows” in a Passive House?

Big windows should be avoided, because 1m2 consumes energy as much as a wall of 5-10 m2. In addition, a tall window may cause draught, because if its height is close to 2m, the air in front of it will cool down.

Should the windows of a Passive House face South?

Sun energy does not flow only from the South but also from the East and the West. Positioning windows to face South and West makes most use of sun energy. At the same time one should keep in mind the shading outside during the summer in order to avoid high room temperatures.

Can a folkhouse be built as a Passive House?

There is no clear definition of a folkhouse. Small-checked windows are usually associated with the appearance of a folkhouse. Small windows decrease the consumption of energy. Also bearing wall and heat charging fireplaces are associated with folkhouses. However it is possible to use the heat from a fireplace only when the temperature is less than zero Celsius -- otherwise room temperature can rise too much. If a folkhouse is perceived as “breathing” and tenuous it is not a Passive House.