Replacing an old Valmet unit with a new ventilation unit connected to geothermal heat
Best known for his rally career, Henri Haapamäki, AKA Haabägi, renovated his house’s energy systems in autumn 2024 and switched from oil heating to geothermal heating. During the renovation, the decades-old Valmet Kotilämpö system was switched to a Vallox Aito Kotilämpö air heating unit.
This 400 m2 detached house has two floors and over 200 m2 that need heating. Living spaces are located upstairs while the downstairs area is reserved for storage spaces and the boiler room. The house utilises air heating, meaning that the heat is distributed evenly between rooms through ventilation ducts and supply air valves that are placed on the floors.
Air heating is a common heating method, especially in houses built in the 1970s and 1980s. An air heating unit can be connected to all heating systems from oil to electric, but also to geothermal systems – and this is exactly what Haapamäki wanted for his house as part of the heating renovation.
Before the renovation, Haapamäki was still using the original air heating unit Valmet Kotilämpö.
‘I’ve been replacing it part by part all these years! And yeah, I’ve been frustrated that none of the controls have been working for a long time,’ Haapamäki says, looking over the old unit as it lays where it has been taken down.
The Finnish origin and good advance information about the ease of installation helped with the decision-making
Haapamäki was a little worried that the old unit might break down completely – after all, it had been in continuous use since 1981. That made the decision to get a new unit easy.
‘Getting a new unit is an investment in the future in the same way as a window or roof renovation – equally as important. You can’t forget about it, even if the old unit was still kind of working. When you live in a 50-year-old house, you gotta do something,’ Haapamäki says.
It only took a few days for the skilled experts to swap out the old unit for a new one.
‘Choosing Vallox was easy: I could get instructions and the website in my language, and the website also had a great reference case about a similar Kotilämpö unit change. So I already knew that I wouldn’t need to blow apart the whole building, but the worksite would be pretty easy to manage.’
After installing the unit, the next step is measuring and adjusting air flow volumes and checking the settings to make sure that the system is as energy-efficient as possible. This is a job for someone who knows what they’re doing and can adjust the air volumes specifically for an air heating site.
‘If possible, it is best to measure room-specific air volumes before dismantling the old unit and system. This makes it easier to get to where we started from before the change of the unit,’ says technical expert Olli Löppönen from Vantaa.
If you haven’t written down the old air volumes, you can download an Excel-based calculator on the Vallox website that helps you calculate the supply air volume of a maximum 10 rooms quickly and easily.
Energy-efficient Vallox Aito Kotilämpö replacing Valmet Kotilämpö
The old Valmet Kotilämpö air heating unit was replaced with a Vallox Aito Kotilämpö unit which was manufactured in the same factory as the old Valmet. Vallox Aito Kotilämpö has, in fact, been designed to be able to replace Valmet Kotilämpö units – the most manufactured air heating unit of all time – without major duct system modifications.
The air heating part of Vallox Aito Kotilämpö features a 6-row liquid radiator. It helps heat up the house efficiently with no draught, thanks to its low circulating air volume. The radiator and the ventilation utilise the same control panel, and there is a separate 4-phase control to adjust the speed levels of circulating air which can be pre-selected steplessly.
The ventilation part features a cross-counter flow cell to stop the odour and moisture of extract air from mixing with supply and circulating air. The unit’s annual efficiency of heat recovery is approximately 77%. This value indicates the amount of heat that the heat recovery system can recover from the extract air on average throughout the year in order to heat the supply air.
‘I think the biggest difference to the old unit is this heat recovery feature, so we are no longer feeding heat to the birds on the roof, but the house gets to keep all the heat,’ Haapamäki comments, clearly happy after the renovation.
The automated defrosting keeps the efficiency high, even in cold weather. All fans of the new air heating unit are energy-efficient DC fans (EC), which cuts their energy consumption down to around half of that of old air heating units with AC fans.
Indeed, Haapamäki’s goal was to save energy, and through that, money. He is planning to keep a close eye on the units’ energy consumption for the first year and report on his YouTube channel how his house’s energy consumption has changed after the renovation.
‘I’ve promised to report the results honestly, as to how well the units are actually performing,’ Haapamäki swears.
The first impression of his new unit has been positive, and during the first month of use, he says that the indoor air has been sufficiently warm and fresh.
‘What is great about this new unit is that all the fans and other parts are conveniently displayed, so maintenance and cleaning the unit have been easier than before.’
It is best to check the cleanliness of the heat recovery cell about once a year and wash the cell, e.g. by hosing it down on the bathroom floor. It is recommended to change the filters twice per year. One filter package (No. 30) includes all the filters needed for one exchange.
Controlling ventilation from the kitchen
Vallox Aito Kotilämpö enables controlling the ventilation and indoor temperature through the MyVallox Control panel.
‘The control panel displays all sorts of useful information: temperatures, moisture and carbon dioxide levels, fan speeds, and things like whether the heat recovery function is on or off,’ Haapamäki lists while browsing through the control panel’s menu.
In Haapamäki’s house, the ventilation modes (e.g. At home and Away) can now be adjusted even from the kitchen, thanks to the Vallox Delico PTD EC cooker hood.
Vallox Delico captures smoke excellently and, on top of everything else, the unit even looks stylish, so it easily finds its place in the existing kitchen.
‘I really like to cook, so things like ventilation efficiency, sealing and style are a great addition there.’
In addition, the use and maintenance of the cooker hood are easy: the touch buttons are lit, the steam collection part slides out, and the LED lamp in the hood provides a good light for cooking, The glass panel is easy to keep clean and the aluminium grease filter can be washed in the dishwasher.
‘My wife has been responsible for filter changes until now, but I think soon that’ll be my job, too, since it’s so easy now,’ Haapamäki jokes.
Fresh indoor air – better quality of life
The indoor air of the house is adjusted through the readings of the temperature sensor located in the opening for circulating air or a separate room temperature sensor. A separate sensor can be placed in a location that best represents the house’s temperature.
The ventilation part of the Vallox Aito Kotilämpö is equipped with built-in carbon dioxide and moisture sensors that increase the air flow e.g. when they detect a rise in air humidity or carbon dioxide values after a shower or when the house fills with guests. Ventilation can be further automated through the external moisture, carbon dioxide and VOC sensors.
Running the unit becomes effortless with the sensors as the user does not constantly need to adjust the settings and modes. The result is constantly fresh, sufficiently warm indoor air. ‘One of my starting points for the unit change project was improving my quality of life, even though that’s kind of an idealistic goal, but if I can at least get the house to smell great, that’s already a big deal!‘