Changing Mechanical Exhaust Air to HRV

Att byta mekanisk frånluft till FTX kan bli ett rejält lyft för villaägare som vill få bättre inomhusluft, jämnare temperatur, bättre styrmöjligheter och framför allt minska värmeförlusterna. I ett hus med mekanisk frånluftsventilation sugs luften ut med fläkt, medan ny luft ofta kommer in genom väggventiler, fönsterventiler eller otätheter i huset. Det fungerar, men mycket av värmen i inomhusluften försvinner rakt ut.

Here we go through how a change from mechanical exhaust air to FTX can be done, estimate the cost, what benefits are available and what you should consider before getting a quote.

What is FTX ventilation?

HRV stands for exhaust and supply air ventilation with heat exchange. This means that the system both extracts used air and supplies new, filtered air using fans. The difference from conventional mechanical exhaust air is that FTX also has controlled supply air and heat recovery.

In practice, it works like this:

• Exhaust air is extracted from bathrooms, toilets, laundry rooms and kitchens.
• Supply air blown into rooms where you spend a lot of time, such as bedrooms and living rooms.
• The heat exchanger utilises the heat in the exhaust air (usually 80-85%) and preheats the incoming outdoor air.
• Filters cleans the supply air from pollen, particles and dirt before the air enters the home.

Konkreta skillnader mellan mekanisk frånluft och FTX

Mechanical exhaust is a simpler ventilation system: a fan creates negative pressure in the house and extracts air from wet rooms and other exhaust spaces. New air enters through vents or leaks. The system can work well, but it offers less control over air flows and no heat recovery.

Some advantages of switching from mechanical extract air to FTX

1) Energy saving

One of the main reasons for switching to FTX is to reduce heat losses. In a standard exhaust air system, heated air is vented out of the house. With FTX, a large part of the heat is recovered and used to heat the fresh air coming in.

The amount of energy saved depends on the size of the house, its airtightness, insulation, heating system and the current ventilation system.

2) Better and more even indoor climate

FTX provides a more controlled airflow. Fresh air is supplied where it is needed and used air is removed from areas with moisture, odours and pollutants.

Benefits that homeowners often experience:

• fresher air in bedrooms and living rooms
• less trapped odours
• better moisture management in bathrooms and laundry rooms
• more even ventilation all year round
• less draught from cold supply air vents

3) Filtered supply air

An FTX system filters the air before it is blown into the home. This can be a big advantage if you live close to traffic, in an urban area or in an area with a lot of pollen. Filters need to be changed about 2 times a year, but they also help keep incoming air cleaner and reduce wear on components in the unit.

4) Better solution after renovation

Many older houses become more airtight after renovation, for example when replacing windows, adding insulation or sealing the building envelope. In this case, an older exhaust air system may start to malfunction because the supply air no longer enters in the same way.

If you are planning a major renovation, it may therefore be a good time to review your ventilation at the same time and see if FTX is the right solution.

What is the cost of changing mechanical exhaust air to FTX?

Kostnaden för att byta från mekanisk frånluft till FTX varierar mycket. Det som påverkar priset mest är husets planlösning, kanaldragning, nödvändiga genomföringar, val av FTX unit, hur mycket av det befintliga systemet som kan återanvändas och om du kan acceptera en mer synlig dragning av kanalerna.

As a rough guideline, a FTX installation in a house often somewhere between about SEK 80,000 and 180,000 before any ROT deduction. Simple unit replacements can be cheaper, while installations in older houses with difficult ducting can be more expensive.

Observera att priserna endast är uppskattningar. Den faktiska kostnaden kan först bedömas när en installatör har gått igenom huset, befintliga kanaler, möjlig kanaldragning och placering av aggregat.

Please read our article on cost of FTX ventilation if you want to dig deeper into the price picture.

When is it worthwhile to switch to FTX?

A switch to FTX is often most interesting when several of the following points apply:

• the house has high heating costs
• you experience draughts or cold air from vents
• you have problems with bad air, odours or moisture
• the house is relatively tight or will be sealed during renovation
• you are planning a major renovation where ducting will be easier
• you want to improve comfort, not just cut energy costs

FTX should be seen as both a comfort investment and an energy investment. In some houses, the savings are clear. In others, the biggest gain is better air, more even temperatures and a more controlled ventilation system.

When is FTX not the obvious choice?

FTX is not always the best solution. If the house is very leaky, if the ducting requires major interventions or if the heating cost is already low, other measures may be more reasonable.

For example, it may be better to review first:

• cleaning of existing ducts
• adjustment of current ventilation
• replacement of exhaust fan
• more or better positioned supply air vents
• local measures against moisture, odour or poor airflow

En fackkunnig installatör bör kunna hjälpa dig att bedöma om FTX är rätt lösning för just ditt hus.

Important to consider before switching to FTX

Check the ventilation that exists today

Start by finding out how the current ventilation is working. Sometimes problems are due to dirty ducts, closed valves or incorrect air flows rather than the whole system needing to be replaced.

Review the tightness of the house

FTX works best in a house that is reasonably tight. If a lot of air is leaking in and out through leaks, it will be more difficult to control airflows, and energy gains may be lower.

Plan your ducting carefully

Ducting is often the biggest challenge when switching from mechanical extract air to FTX. In existing houses, ducts are often routed via attics, basements, storage rooms, wardrobes or new cladding along walls and ceilings.

Ask the installer to show you how the ducts will be laid before you accept the quote. This will make it easier to understand the cost, the intervention and the final result.

Choose a practical location for the unit

The FTX unit needs to be located so that it can be accessed for filter replacement, service and cleaning. Common locations are technical rooms, utility rooms, attics, basements or storage rooms.

A location that looks good on a drawing may be impractical if the unit is difficult to reach in everyday life.

Don't forget the noise level

Ett väl installerat FTX-system ska inte störa. Ljud kan komma från aggregatet, luftflöden i kanalerna eller från donen i rummen. Därför är rätt dimensionering, isolering av kanaler, ljuddämpare och genomtänkt placering viktiga delar av installationen.

Think about the cooker hood

The kitchen fan inlet duct should normally be managed separately from the FTX system. Grease and cooking vapours should not be led into the heat exchanger. This needs to be properly planned from the start.

How a switch to FTX usually works

1. Walk-through of the house: The installer checks the existing ventilation, floor plan and possible duct routes.
2. Dimensioning: Air flows and units are customised to the size and needs of the dwelling.
3. Plan for ducting: You decide where to place the ducts, diffusers and units.
4. Offer: You will receive prices for materials, labour, equipment, ducting, soundproofing and tuning.
5. Installation: Ducts, valves, units, bushings and insulation are installed.
6. Adjustment: Air flows are measured and adjusted så att FTX-systemet fungerar som det ska.

What should a good quote include?

When you get a quote for changing from mechanical exhaust air to FTX, it should be clear. It should be possible to see what is included and what may be added.

Please ask for the quote to specify:

• which FTX unit is included
• how the canals should be routed
• number of supply and exhaust air outlets
• what insulation and soundproofing is included
• if piercing and restoration are included
• if electrical work is included
• if adjustment and protocols are included
• guarantees on labour and products
• calculated ROT deduction, if applicable

Common mistakes to avoid

• Only choosing the cheapest offer: Always compare what is actually included, not just the total price.
• Underestimating channelling: Poor ducting can lead to more noise, poorer airflow and unnecessary interventions.
• Placing the unit too inaccessible: Filters need to be changed regularly and the unit needs to be serviceable.
• Skipping alignment: An unadjusted FTX system can result in incorrect air flows, noise and poor performance.
• Forgetting about maintenance: Filters, nozzles and aggregates need to be checked for the system to function well over time.

Få offert på FTX-ventilation

Do you want to know what it would cost to change mechanical exhaust air to FTX in your house? Contact us for a quote på installation av FTX. Offerten tas fram av våra certifierade samarbetspartners som kontaktar dig och går igenom husets förutsättningar och möjliga lösningar.