Heat Recovery Ventilation FAQ

Want to know more about heat recovery ventilation?

Get That Summer fresh air feeling all year round

Recovers heat that would otherwise be lost to extract ventilation. Summer Fresh draft free home even in winter. 

Can you boost the Heat Recovery Ventilation System to remove bad odours?

 ‘set it and forget it’

Occupant-controlled Boost function.

Boost switches are located in the kitchen, utility and outside toilets, bathrooms and ensuites.

With a “Push of a switch”, the Boost increases fan speed to the highest setting, increasing airflow on demand, and is ideal when large gatherings in the home require greater ventilation

Boost quickly improves indoor air quality in any room of the home where air suddenly becomes undesirable or contaminated from sources such as large social gatherings, cooking vapours, crowds, smoke and bad odours.

What are the fan speed settings for Heat Recovery Ventilation System?

The unit has 4 the fan speed settings

  1. 20% Set back mode during sleeping hours
  2. 30% Normal mode
  3. 50% Boost mode by pushing a boost switch to remove bad odours or will automatically with rise in humidity due to cooking or showers.  
  4. 100% Purge mode  by holding the boost switch on the controller down for 5 seconds  the unit will run at 100% for 2 hours to quickly remove bad  odours or cool the down the house when it is in summer bypass mode. The purge mode  will automatically turn of after 2 hours or can be deactivated by holding the boost switch on the controller down for 5 seconds

Can Heat Recovery Ventilation cool houses?

Struggling to get to sleep on hot summer nights during a heat wave?

Yes the Heat Recovery Ventilation systems contributes to cooling homes during the summer this works by a summer bypass

Overheating due to global warming, increased levels of insulation, airtightness and solar gain through windows & glazing patio doors is becoming more frequent                                    

Unlike air conditioning units which cools air by refrigerant technology recycling it back to the room consuming a lot of electricity.

The Heat Recovery Ventilation system works by bypassing the heat exchanger when the outside temperature is above 14 °C and the inside temperature is above 24 °C.

Such as in the evening & early night when people are going to bed and are struggling to sleep due to the heat but can’t leave the windows open due to security concerns and flying insects

The advantage of Heat Recovery Ventilation is that windows can be shut at night, cool fresh air is drawn from outside and it is extremely economical to run

The warm air is flushed out and cool fresh air is drawn from outside.

With “Push of a switch”, purge mode you can boost the unit to 100% purge mode for2 hours

After which the unit returns to normal mode and it runs at 20% during sleeping hours

Cool down house during hot summer nights

Why is balancing and Commissioning of Heat Recovery Ventilation systems Important?

Crossan Energy balance and commission all our Heat Recovery Ventilation systems using an anemometer to verify design flow rates and compliance with Irish Building Regulations Part F 2019 are achieved.

We give a 5 year parts and labour warranty when serviced annually by Crossan Energy.

Why is it important to change filters and service the Heat Recovery Ventilation system?

We recommend that the Heat Recovery Ventilation system is serviced by Crossan Energy once a year as filters will gradually become clogged as the year progresses and this will affect the efficiency of the unit.

In between services we recommend that the home owner to checks the filters and gently  hovers hem at low speed to clean, and reinstate them the same way round as they were before.

How much noise do Heat Recovery Ventilation System emit?

Heat recovery ventilation systes emit very little noise and will certainly not be heard above background noise such as a shower or fridge.

During sleeping hours the unit has is set back to very low speed that reduce noise to less than a quiet whisper.


Kilmore Upper


Co. Longford


087 98 98 434


Heat recovery ventilation unit & ducting in attic

Ducting through partition walls.

Duct Runs in timber joists

Duct Runs in timber joists

Duct Runs through Easi-joists

Ducts installed between concrete slab & metal ceiling

Air Valves