What is the difference btw a HRV, a ventilation unit/air handling unit

v638sg7k1a92bx

We're renovating the office and need new heating system. office is about 125sqm GF and basement with the GF being a mezzanine floor. I'm trying to decide on what heating system to use bearing in mind that we will need some type of air extraction/ventilation. With that in mind I| was thinking if we need to get ventilation should we also incorporate the heating system in that so that all the ducting is done at the same time but as a micro business cost is also a big consideration.

I've been looking at the various options but can anyone explain the difference between a HRV and a ventilation unit as I can't seem to find the difference from searching google or would installing electric rads be the easiest solution?

littlemissfraze

Ulises Icy Bumper wrote: »

We're renovating the office and need new heating system. office is about 125sqm GF and basement with the GF being a mezzanine floor. I'm trying to decide on what heating system to use bearing in mind that we will need some type of air extraction/ventilation. With that in mind I| was thinking if we need to get ventilation should we also incorporate the heating system in that so that all the ducting is done at the same time but as a micro business cost is also a big consideration.



I've been looking at the various options but can anyone explain the difference between a HRV and a ventilation unit as I can't seem to find the difference from searching google or would installing electric rads be the easiest solution?

When you say that you "need some type of air extraction/ventilation" can you explain? Does the office have openable windows?

You will need some sort of mechanical ventilation if you do not have natural ventilation (openable windows). You should size your mechanical ventilation based on 10litres/second/person if it is required.

HRV is basically when the heat is recovered from air that would normally be exhausted. A non hrv ventilation unit (air handling unit) does not have a heat exchanger.

Can you describe your office in more detail..
Occupancy, Windows? Existing heating system?

Cheapest capital cost would be electric rads but they'll cost a fortune to run.
In between option is boiler with radiators.
Heat pumps are popular in new builds but require good levels of insulation

v638sg7k1a92bx

littlemissfraze wrote: »

When you say that you "need some type of air extraction/ventilation" can you explain? Does the office have openable windows?

You will need some sort of mechanical ventilation if you do not have natural ventilation (openable windows). You should size your mechanical ventilation based on 10litres/second/person if it is required.

HRV is basically when the heat is recovered from air that would normally be exhausted. A non hrv ventilation unit (air handling unit) does not have a heat exchanger.

Can you describe your office in more detail..
Occupancy, Windows? Existing heating system?

Cheapest capital cost would be electric rads but they'll cost a fortune to run.
In between option is boiler with radiators.
Heat pumps are popular in new builds but require good levels of insulation

This is a drawing of the unit https://imgur.com/a/VgKV167. The just conceptual drawings, we may have open plan workspace rather than offices.

It's an ex retail unit now being used as an office, the only windows are the entrance to the front and a skylight/access window in the meeting room at the back of the building on the GF.

Jjpc84

In English, rather than the google copy above, hrv systems take air from warm rooms (ie. bathroom, kitchen, utility,) and run next to (but seperate to) air pushed into the building. It does not heat up the building. It warms the air coming in and your heating system takes over. Hrv will not heat you’re office’s.

littlemissfraze

Jjpc84 wrote: »

In English, rather than the google copy above, hrv systems take air from warm rooms (ie. bathroom, kitchen, utility,) and run next to (but seperate to) air pushed into the building. It does not heat up the building. It warms the air coming in and your heating system takes over. Hrv will not heat you’re office’s.

"Google copy above"?!

It is possible to heat your office using an air handling unit with heat recovery and a heating coil. This would normally only be done however if you have a large fresh air requirement e.g call centre, lecture theatre etc.

Stick to your domestic nixers Jjpc84

v638sg7k1a92bx

littlemissfraze wrote: »

When you say that you "need some type of air extraction/ventilation" can you explain? Does the office have openable windows?

You will need some sort of mechanical ventilation if you do not have natural ventilation (openable windows). You should size your mechanical ventilation based on 10litres/second/person if it is required.

HRV is basically when the heat is recovered from air that would normally be exhausted. A non hrv ventilation unit (air handling unit) does not have a heat exchanger.

Can you describe your office in more detail..
Occupancy, Windows? Existing heating system?

Cheapest capital cost would be electric rads but they'll cost a fortune to run.
In between option is boiler with radiators.
Heat pumps are popular in new builds but require good levels of insulation

Hoe expensive are electric rads to run as I see them in offices everywhere? I thought the electric rads were much more efficient now?

If I was to install a HRV system with oil filled electric rads then I expect that much be much cheaper to run, with the insulated walls and ceilings combined with the HRV I expect that the rads wouldn't need to be turned on as much.

As I'm discovering more about this, I don't think heating and ventilation will be as much of a problem as the office being too warm in the spring and summer because HRV will only maintain the temperature inside the room and so it's not going to reduce the temperature. Do you know if cooling units can be attached to a HRV or are we into air conditioning now?

Calahonda52

There is no such thing as an efficient elec rad, unless you include the use of thermo stats rather than the old boxes of sand

any decent HRV unit will have a summer bypass so it will deliver outside, filtered but not preheated.

Yes cooling coils can be fitted, however remember that as humid air is cooled, it will increase the RH and when you get to the dew point, the moisture vapour will sort to condense out, with the air still at 100% RH.
That is why A/C in AHU's is so expensive as you cool down to maybe 6C, or less, to get out most of the moisture vapour, and then heat it back up again, with some outside air mixed in, depending on the complexity of the A?C unit.

If you think you will need cooling, then look at a few wall mounted heat pumps fior heating and cooling, however they will not condition the RH.
If you use them make sure to mhave a good dead band so as to avoid heating/cooling. Also get ones where the controller can be programmed to shut down at 17:00 and not start before 09:00, with a manual override restricted to say 15 minutes

v638sg7k1a92bx

Calahonda52 wrote: »

There is no such thing as an efficient elec rad, unless you include the use of thermo stats rather than the old boxes of sand

any decent HRV unit will have a summer bypass so it will deliver outside, filtered but not preheated.

Yes cooling coils can be fitted, however remember that as humid air is cooled, it will increase the RH and when you get to the dew point, the moisture vapour will sort to condense out, with the air still at 100% RH.
That is why A/C in AHU's is so expensive as you cool down to maybe 6C, or less, to get out most of the moisture vapour, and then heat it back up again, with some outside air mixed in, depending on the complexity of the A?C unit.

If you think you will need cooling, then look at a few wall mounted heat pumps fior heating and cooling, however they will not condition the RH.
If you use them make sure to mhave a good dead band so as to avoid heating/cooling. Also get ones where the controller can be programmed to shut down at 17:00 and not start before 09:00, with a manual override restricted to say 15 minutes

Are those heatpump systems not alot more expensive? It would take years to recover the capital costs. I could stick a few dyson fans around the place in the summer to keep the place cool

Calahonda52

Ulises Icy Bumper wrote: »

Are those heatpump systems not alot more expensive? It would take years to recover the capital costs. I could stick a few dyson fans around the place in the summer to keep the place cool

.
If thats all you have to say, good luck

v638sg7k1a92bx

Calahonda52 wrote: »

.
If thats all you have to say, good luck

Yes but if I have a HRV which will maintain the heat in the building then I won't have to heat the building as much so the cost of installing heat pumps isn't justified because the running costs of the electric rads will be less and to recover the cost of a heat pump would take at least 10 years in electricity bills, see what I mean?

Gumbo

Ulises Icy Bumper wrote: »

Yes but if I have a HRV which will maintain the heat in the building then I won't have to heat the building as much so the cost of installing heat pumps isn't justified because the running costs of the electric rads will be less and to recover the cost of a heat pump would take at least 10 years in electricity bills, see what I mean?

All renewable, sustainable products are an investment.
They all have a ROI that is to be measured in years.

v638sg7k1a92bx

kceire wrote: »

All renewable, sustainable products are an investment.
They all have a ROI that is to be measured in years.

But over what period of time, and by that stage is the technology redundant? It has to make sense from a business perspective. For example, if I'm going to save €200 per month in ESB bills but I have to pay €25k for a Heat Pump then I would rather pay the extra €200 per month.