When Maria Klemetz and Janne Käpylehto were looking for a new home for their family, they had a clear goal in mind. The hope was to find a house built before 1950 near the Old Town of Helsinki. The area is known for its old houses with cosy gardens. The couple had time to inspect a dozen or so properties before they found the right one.

– We were desperately looking for a suitable house on the Käpylä-Kumpula-Toukola axis. The task was not easy, as we both need our own workspaces at home. Our home wasn’t even for sale when we first saw it a couple of years ago, says Janne Käpylehto.

– From the outside, the three-storey house had a suitable personality and diversity, which made an immediate impression on both of us, confirms Maria Klemetz.

What made the house special?

– When we finally got to see the building from the inside, it was even better than we expected. By then, the functionalist house, which had already seen its best days, had last been renovated in the 1980s. But we immediately recognized several fantastic structural solutions: wide windows, tall windows, arched windows and an impressive 6.5-meter room height in the entrance hall.

An old house is an adventure

Klemetz’s and Käpylehto’s own backgrounds made it easier to plan the renovation. The architect and technology innovator had a clear vision of how to restore the middle-class home from 1939 to its former glory, but at the same time also suitable for everyday life in a modern family with children. In addition, they wanted to use traditional building materials as much as possible.

– It was clear from the beginning that we don’t want structures that don’t breathe in our home. Frankly, we wanted to avoid all plastic as much as possible, explains Käpylehto.

The division of labour was clear, Maria Klemetz took over the responsibility as main designer. The people who carried out the renovation were found through the couple’s own network and with the help of neighbours and recommendations.

As always when carrying out renovations, surprises were not avoided this time either.

The extensive surface renovation, which was supposed to take a few months, turned into a two-year work camp and the budget was tripled. The family also managed to grow during this time. But the result is exactly what was hoped for – a home where it is easy to breathe.

Indoor climate solutions on the residents’ terms

The house had gravity ventilation characteristic of the construction period, which we wanted to preserve. It was clear from the start that we needed a different kind of solution for the bedrooms.

– In my work, I had already gotten to know different ventilation solutions, so we knew that there are many different options, confirms Maria Klemetz.

The couple found suitable units from Zehnder through traditional Googling. The ComfoSpot 50 was chosen for several reasons. It is easy for Janne Käpylehto to list the qualities that weighed heavily in the scales during the election. According to him, even a water-circulating radiator sounds more than the ventilation units in the bedrooms.

– ComfoSpot 50 is so quiet that it could also be installed close to the bed. The appearance was of course also important, i.e., the fact that the unit’s indoor and outdoor unit can be masked. You can practically forget about the unit’s existence, as the automation adjusts the flow rate by itself. The only thing you need to do is change the filter. The indoor air in the bedrooms has been healthy since the installation and I have told many people that it feels like sleeping outside in a tent, summarizes Käpylehto.

Zehnder ComfoSpot 50 is a room-specific ventilation unit with heat and moisture recovery and continuous supply and extract air flow. It is intended for ventilation of individual rooms in both renovation and new construction projects. The unit has an enthalpy heat exchanger as standard equipment, which guarantees high heat and moisture recovery. The Zehnder ComfoSpot 50 can be equipped with various external wall panels or a window module, which means that the unit’s supply and extract air duct can be almost imperceptibly embedded in the window frame.

The importance of a good indoor climate is particularly emphasized during the winter months, when we spend a lot of time at home and indoors. Enervent Zehnder’s ventilation units have been specially designed for the northern climate and varying weather conditions have been considered in our product development from the beginning.

Our units are designed to cope with large differences between indoor and outdoor temperatures. The most important thing is to remember to use the unit according to the instructions in all situations. The dimensioned air volumes should not be changed, even if it is very cold outside. When used correctly, the units do not freeze even if the humidity in the extract air rises temporarily.

In addition, the technology solution we chose – the rotary heat exchanger – is a known energy-efficient alternative.

During the winter months, the humidity decreases

In winter, heating dries out the indoor air and it is important that ventilation devices balance the humidity. When the temperature drops below 0 °C, the rotary heat exchanger recovers some of the moisture in the extract air, so that the indoor humidity remains at a healthy level.

Clean filters ensure fresh air

Our units work best when the user remembers to change the filters regularly. It is recommended that the filters in the ventilation unit be replaced at least every six months. Now is a good time to make sure new filters are ordered for the unit for the cold winter months.

The energy-saving eco mode

Our ventilation units have an energy-saving eco mode. Its purpose is to minimize the ventilation unit’s electricity consumption and maximize heat recovery, without impairing the ventilation. Using the eco mode may temporarily cause a feeling of draft on cold winter days, but at the same time provides savings in operating costs.

In the spring, Enervent Zehnder started a collaboration with Filterpak from Hanko in Finland. The company is known as a manufacturer of high-quality filters. Filterpak belongs to the Finnish M-Filter group, which has versatile air filter expertise, from small ventilation unit filters to special filters for industry.

Roger Lindström, who has been responsible for Filterpak’s sales for more than six years, confirms that the company has continuously invested in growth and business development in recent years.

– Filterpak changed owners in the early 2000s, when Thomas and Peter Nordlund bought the entire business from its founder. From the beginning, they had a strong vision in which direction the company should be developed. We wanted to build Filterpak into a company that promotes people’s health through innovation, says Lindström

Just before the pandemic started, the company made a big investment in expanding production. The delay in the delivery of new equipment slowed down the reforms, but according to Roger Lindström, it also brought surprising opportunities. Filterpak began manufacturing domestic surgical mouth-nose masks.

– The technology develops and Filterpak renews its equipment base at a fast pace. Currently, the most important product groups for our company are cassette filters and bag filters. Enervent Zehnder’s ventilation unit uses both solutions.

Filters are more important than you might think

In home ventilation units, the quality of the filters plays a key role. If the pressure loss is not correct, the air volumes in the unit do not remain balanced and the ventilation unit does not work correctly. The right kind of filter is also important when it comes to energy efficiency.

– Our product is undeniably quite special because it is always hidden inside the units. In addition, its task is to filter out particles from the air that are invisible to the human eye, notes Lindström.

– The filters we produce for Enervent Zehnder are not off-the-shelf items – when it comes to ventilation units, both bags and cassettes are tailored for each type of unit. This is the only way to ensure full compatibility of different unit models. Our collaboration has worked well here since the beginning.

Partnership is development together

Filterpak’s operating philosophy includes long-term cooperation with partners. The customer owns the product, but Filterpak develops it for them. Together, we carry out continuous evaluation and further development.

– Although we have invested in automation of work steps, the products are unique. In the work phases, manual work and human supervision are also still needed. We have very committed and competent staff in Hanko.

– We are proud of all our products. The cassette filters used in Enervent Zehnder’s units are 100 % domestic. Their fiber material is manufactured by Ahlström-Munksjö in Tampere, the glue comes from the family company Kiilto and we manufacture the filters for the ventilation units which are manufactured in Porvoo. A chain of four companies with Finnish work and know-how in them, summarizes Lindström.

Mikael Karlsson, who is responsible for Enervent Zehnder’s supply chain, confirms that the collaboration with the domestic filter manufacturer is also significant for the company from an economic and environmental responsibility point of view.

– The development together with Filterpak has already proven to work during the first year. By keeping supply chains short, our operations also have low emissions, which strongly supports our responsibility goals. We also wanted to do our part to influence the preservation of jobs in Finland and find a high-quality operator to which we can concentrate the production of filters.

Photo of Roger Lindström by Miikka Pirinen. Read more about M-Filter Group >>

This year, the jury of the Highlights competition at the FinnBuild trade fair selected nine candidates to compete for the award for the fair’s most interesting innovation. Enervent Svea eAir E Cooler is included in the group. A ventilation unit designed and manufactured in Finland, which can have integrated compressor cooling, renews the cooling of homes.

After a four-year break, Finnbuild, a meeting place for construction industry operators, will take place at Helsinki Messukeskus in October. In the Highlights competition, the fair’s most interesting product, system and service is searched for. Enervent Svea eAir E Cooler is one of the nine selected.

The change in living requirements has increased interest in various cooling options in recent years. So far, there have only been a few options available for households. In addition to air source heat pumps, the traditional hybrid models that were previously on the market were primarily designed for commercial and office premises or restaurants. The Cooler unit developed by Enervent Zehnder to be integrated into the Svea ventilation unit brings a solution to the situation.

Svea’s Cooler unit meets customer needs

Thanks to the advanced fan technology, Svea corresponds to devices of larger size, but requires relatively little space. Despite its small size, the ventilation unit has both a rotating heat exchanger, an 800 W after heater and energy-efficient direct current fans. Enervent Svea was designed in such a way that a separate module can be placed on top of the ventilation unit. The module can contain a compressor cooling unit or, for example, water-circulating heating and cooling coils.

– Especially in new housing production, there has been a clear need for a unit that can integrate compressor cooling for a long time. Svea can be installed on the wall or ceiling. The Svea Cooler combination does not require larger space, but only increases the height of the device. The structure works like Lego blocks, and the Cooler can be retrofitted to previously purchased Svea devices, summarizes Ronni Laaksonen, who is responsible for sales at Enervent Zehnder.

The advantage of Svea Cooler is that the cooling is achieved without draft. The cooling is evenly distributed in all rooms with an supply air valve. This is a clear improvement compared to, for example, a traditional air source heat pump that only cools the space where the indoor unit is. Svea Cooler also does not need a separate outdoor unit.

Responsibility involved in development work

All of Enervent Zehnder’s product development is done at the company’s offices in Porvoo, Finland. In the same premises, there is also a climate laboratory that performs continuous testing.

– In our operations, we also want to consider the environmental impact of the company and our products. The new generation R32 refrigerant is used in Svea Cooler. It has a lower environmental load and lower climate effects than older refrigerants, Laaksonen confirms.

Deliveries of the Cooler module will begin this fall. The global shortage of raw materials has affected, among other things, deliveries of evaporator coils, which has slowed down the production schedule.

Jury of the Highlights competition:

lkka Salo, CEO, Talteka
Tapio Kivistö, editor-in-chief, Rakennuslehti
Elina Samila, circular economy expert, Green Building Council Finland
Piia Sormunen, Professor of Building Technology Industry, University of Tampere
Antti Aaltonen, Director, construction development, Construction Industry RT

More information:

Ronni Laaksonen, Head of Sales, Enervent Zehnder Oy, +358 400 230 725, ronni.laaksonen(at)enervent.com

Enervent Svea eAir E Cooler can be seen at the Finnbuild fair, stand 6d 48.