SN Energies, Derrycoosh, Castlebar, Co. Mayo.

Tel: 094 902 8638 Mob: 087 795 3768 Email:

Frequently Asked Questions

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Q. Why should I have HRV? (Heat Recovery Ventilation)

Heat Recovery Ventilation is necessary to gain maximum benefit from insulating and sealing your home. With HRV your home will have a constant supple of clean fresh air, lower heating bills, no condensation, dampness or mould. Members of the household who suffer from allergies, hay fever, respiratory ailments and asthma will greatly benefit from the approved air quality, and radon and carbon gases will be eliminated.

Q. At what stage in the construction process should I install my unit?

The HRV unit should be installed when the roof is on, before first fix, ideally just before plumbing work is undertaken. The unit should be run and pressure tested before covering over duct work.

Q. Will it work / is it compatible with my heating system?

Heat Recovery Ventilation systems work in conjunction with your heating system, regardless of type and no inter-connection is required.

Q. Can I connect the extract from the cooker hood to the unit? Why?

No. the extract from your cooker hood should not be connected to the HRV unit. Grease from the cooker hood will block the filters in the unit more quickly and may coat the heat exchange, reducing heat recovery efficiency.

Q. Can the unit be installed in an existing building?

Yes. Retro-fitting a unit is possible. It is easier to install the ductwork in a single story house, although it has been retro-fitted also to multi-story buildings, routing ground floor duct work between floor joists and down the rear of hot presses and wardrobes.

Q. Can I ventilate part of a house only?

A section of a house can be ventilated (for example the 1st floor bedrooms and bathrooms of a two story house), but for maximum benefit it is recommended to ventilate the whole house to ensure healthy conditions throughout and to prevent condensation.

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Q. Where should ductwork be located?

If installing in the attic space, try to keep towards the eaves of edges of the attic so that the attic remains as unobstructed and usable as possible.

Q. Where do I locate the fresh air inlet and stale air exhaust louvres/cowls?

Fresh air should e taken if possible, from the north side of the building or from a shady place where temperature variations are moderately small. This will ensure that, during summer time the Enervent unit will not be bringing in hot air, overheating rooms. During winter time there is little difference in temperature between north facing and other sides. Ensure that the fresh air intake is not positioned near any waste pipes (e.g. boiler flue). Locate the stale air exhaust lourve or cowl far enough away from the intake to prevent recirculation (or short circuiting) of stale air. The orientation of the stale air exhaust is not critical.

Q. What about fresh air intake and stale air outlet points � should I use louvres or cowls? What type of lourve or cowl should I use?

If your building has gable walls louvres are the preferred method of air intake and exhaust. These are easy to weatherproof as the roof structure and membrane are not punctured. Of course your building may not have gables or it may be impractical to use gables, in which case the use of cowls is perfectly acceptable. It is also acceptable to mix and match (e.g. lourve for intake and cowl for exhaust. Whether using cowls or louvres the following are important. The �free area� should be equivalent to the area of the spigot on the Enervent unit. The free area is the unblocked or unimpeded area of an opening. Louvres typically have a free area of 50%. For example the LTR-3 has a 160mm diameter spigot. This has an area of approximately 20,000mm2. If using a lourve with 50% free area then the actual lourve size required is 40,000mm2 or 200x200mm. Where it is impossible or impractical (e.g. due to tile size) to accommodate the free area requirements on one cowl, multiple cowls connected together in parallel can be sued. Bear in mind that the maximum free area of a 100mm diameter connection is 7850mm2, so it would take three of these to be equivalent to a single 160mm diameter connection with a free area of 20000mm2.

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Q. Do I need to insulate the ductwork?

Ductwork, regardless of material type must be insulated. The insulation must include an outer vapour barrier to prevent condensation on the outside surface of the ductwork.

Q. Do I need vents in every room � one to provide fresh air and one to extract stale air?

No. fresh air is supplied to habitable rooms � bedrooms, living rooms, dining rooms etc. stale and moist air is extracted from bathrooms, en-suites, utility rooms etc. air moves gently from the supply rooms to the extract rooms underneath doors and through transfer grilles. Allow 19mm gap between the underside of a door and floor finish to facilitate air movement. This method reduces the amount of ductwork required (only one duct running to each room instead of two) and improves air quality in your home (as moist air and odours do not escape from where they are generated).

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Q. What maintenance is involved with Heat Recovery Ventilation?

Heat recovery units by their very nature require regular maintenance. The Sentinel Kinetic has been designed to facilitate access to enable maintenance to be carried out easily.

Filter maintenance

Fan Filters:

When the unit displays �check filters�, this is a reminder to ensure that the filters are not so dirty that they are blocking the airflow or allowing dirt to pass through. The rate at which the filters become dirty will vary hugely depending on the environment and the activity within the property.

  1. Open the filter flaps and remove the 2 filters
  2. Clean gently by tapping or carefully using a vacuum clearer if necessary.
  3. Replace the filters
  4. Close the filter flaps
  5. Reset the automatic message press and hold the buttons for 5 seconds.

Annual maintenance

Fan Filters:

Change the fan filters.

  1. Open the filter flaps and remove the 2 filters
  2. Insert the replacement filters
  3. Replace the filters
  4. Close the filter flaps
  5. Reset the automatic message press and hold the buttons for 5 seconds.

Unit and heat exchanger cell:

Inspect and clean the unit.

  1. Isolate the mains power supply
  2. Open flaps and remove the two filters
  3. Remove front cover from the unit
  4. Slide out the heat exchanger
  5. Wash the outer cover and heat exchanger in warm water using a mild detergent (such as Milton Fluid) and dry thoroughly.

NOTE: Keep water away from all electrical components and wiring within the unit


Inspect the motors for build-up of dust and dirt on the impeller blades, which could cause imbalance and increased noise levels. Vacuum or clean if necessary.

Condensate drain

Check the Condensate drain tube is secure and clear of debris. Clean if necessary.


Check that all unit and wall-mount fastenings are sufficiently tight and have not become loose. Re-tighten if necessary.

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