Conservatory Air Con Unit

[back2space]

Hi guys, would like to ask for some help for a friend,

A friend has asked me what size air con unit will be required for a south facing conservatory measuring 16 metres squared.

Conservatory is getting very hot even on days where ambient outside temps are 18C. The idea is to have the a.c unit operating with the doors open also to make use of the cooler outdoor air to bring the conservatory down to a suitable temperature.

In winter it is going to be used to heat the conservatory so it is usable all year round. Currently have underfloor heating which is costing a fortune to run.

Budget is tight and friend doesnt want external condenser boxes on the wall outside so I have suggested a through the wall/window unit. Ive mentioned the benefits of inverter systems but as its going to be used on odd days there is no immediate benefit at the moment.

I have done load calcs but not sure what to add on for a conservatory so im still confused.

Can anyone reccomend what size would be required and most reliable manufacturer for these types of units.

If any one would like to quote for a split system for a conservatory please get in touch, this is in the Leeds LS16 area.

Thank you.

[frank]

Hi guys, would like to ask for some help for a friend,

A friend has asked me what size air con unit will be required for a south facing conservatory measuring 16 metres squared.

Conservatory is getting very hot even on days where ambient outside temps are 18C. The idea is to have the a.c unit operating with the doors open also to make use of the cooler outdoor air to bring the conservatory down to a suitable temperature.

In winter it is going to be used to heat the conservatory so it is usable all year round. Currently have underfloor heating which is costing a fortune to run.

Budget is tight and friend doesnt want external condenser boxes on the wall outside so I have suggested a through the wall/window unit. Ive mentioned the benefits of inverter systems but as its going to be used on odd days there is no immediate benefit at the moment.

I have done load calcs but not sure what to add on for a conservatory so im still confused.

Can anyone reccomend what size would be required and most reliable manufacturer for these types of units.

If any one would like to quote for a split system for a conservatory please get in touch, this is in the Leeds LS16 area.

Thank you.

There are a number of confusing statements here that maybe want clarification.

Conservatory is getting very hot even on days where ambient outside temps are 18C.

This is due to the South facing and the amount of Solar Gain which penetrates the building fabric, heating up the air trapped in the conservatory.

The idea is to have the a.c unit operating with the doors open

Why?

also to make use of the cooler outdoor air to bring the conservatory down to a suitable temperature.

This is called 'Free Cooling' so you do not need A/C for this. What you need here is a fan.

Currently have underfloor heating which is costing a fortune to run.

Underfloor heating is one of the cheaper options as it uses lower circuit temperatures, thereby needing less energy input to raise the circuit temperature.

Budget is tight and friend doesnt want external condenser boxes on the wall outside so I have suggested a through the wall/window unit. Ive mentioned the benefits of inverter systems but as its going to be used on odd days there is no immediate benefit at the moment.

Everyone's budget is tight at the moment
Condensing units on the wall or condensers sticking out from windows? is there a difference?
If it's used for every day or just the odd day as you say, the benefits of an inverter over a stop/start compressor are a no brainer.

I have done load calcs but not sure what to add on for a conservatory so im still confused.

Proper load calcs would take into account the 'U' values of the conservatory construction, so you should not need to add anything on. As you/your friend wants to use the A/C for both heating and cooling, any system you choose should be based on the greater heat loss/gain. What I mean is, if the heating requirement is greater than the cooling requirement, then buy a unit designed to satisfy the heating load.

If you are intent on using a 'through the wall' compact unit, have a careful look at the operating envelope of the unit. Most of them are designed to work in ambients not lower than 19C, which is not best suited for the UK market.

[beagle]

I'd think the first thing to do would be to look at fitting Reflex glass or blinds to get the solar gains down to workable proportions, I think there's a 'skin' that can be used on existing glass as well but the name escapes me at the moment.

[acnerd]

I'd think the first thing to do would be to look at fitting Reflex glass or blinds to get the solar gains down to workable proportions, I think there's a 'skin' that can be used on existing glass as well but the name escapes me at the moment.

I agree with you. Solar gain is more powerful than we realise!!!!

[back2space]

There are a number of confusing statements here that maybe want clarification.
This is due to the South facing and the amount of Solar Gain which penetrates the building fabric, heating up the air trapped in the conservatory.
Why?
This is called 'Free Cooling' so you do not need A/C for this. What you need here is a fan.
Underfloor heating is one of the cheaper options as it uses lower circuit temperatures, thereby needing less energy input to raise the circuit temperature.
Everyone's budget is tight at the moment
Condensing units on the wall or condensers sticking out from windows? is there a difference?
If it's used for every day or just the odd day as you say, the benefits of an inverter over a stop/start compressor are a no brainer.
Proper load calcs would take into account the 'U' values of the conservatory construction, so you should not need to add anything on. As you/your friend wants to use the A/C for both heating and cooling, any system you choose should be based on the greater heat loss/gain. What I mean is, if the heating requirement is greater than the cooling requirement, then buy a unit designed to satisfy the heating load.

If you are intent on using a 'through the wall' compact unit, have a careful look at the operating envelope of the unit. Most of them are designed to work in ambients not lower than 19C, which is not best suited for the UK market.

AC is required because on the days where the outside ambient is too hot opening the doors/windows is causing the house to heat up, I know in winter this is a bonus but the underfloor heating is costing more to run than an a/c would.

YOu say they use low powered circuits but this just extends the time the floor heating is on. Sorry I should have made it clear that it was an electric system.

Electric underfloor heating costs a lot more to use than a/c. It is 100% efficient whereas an a/c unit is over that 100% common knowledge.

The a.c will be used to assist the free cooling but there will be days when out at work where will want the unit to be working before getitng home.

A window unit will be mounted through the wall but I have worked out we need approx 6kw of cooling and only 3kws of heating. I am trying to steer him in the direction of a split system, the cost of an inverter isnt much more expensive but this would save him a lot of energy in winter when it doesnt need 6kws of heating.

[back2space]

I'd think the first thing to do would be to look at fitting Reflex glass or blinds to get the solar gains down to workable proportions, I think there's a 'skin' that can be used on existing glass as well but the name escapes me at the moment.

The glass has pilkington blue coating on it already which reduces a lot of the solar gain, and my friend doesnt want to fit blinds as he wants the minimal look.

He is using fans at the moment but this is just stirring the warm air up and is no benefit ive told him at all unless he has them positioned at the door, but they look untidy etc.

[eggs]

Back2Space.

Over the years i have conditioned many, many conservatories.
In the perfect world that Frank lives in, yes you could calculate the heat/cooling load for this conservatory.....if you had all the info like "U values". But it's not likely.

For south facing conservatories, when i am not furnished with the full construction details i always use 450w/m. ie 7.2kw for this given example and it has never failed yet.

Don't let The Pack bite

Eggs

[paul thompson]

get a propper air con contractor in for a quote .

[back2space]

Back2Space.

Over the years i have conditioned many, many conservatories.
In the perfect world that Frank lives in, yes you could calculate the heat/cooling load for this conservatory.....if you had all the info like "U values". But it's not likely.

For south facing conservatories, when i am not furnished with the full construction details i always use 450w/m. ie 7.2kw for this given example and it has never failed yet.

Don't let The Pack bite

Eggs

I was thinking of 7kw unit myself Eggs, better to oversize it than undersize it I see particulary with inverter.

Thank you Eggs.

[back2space]

get a propper air con contractor in for a quote .

At the moment he is not fitting it just wanted rough idea of price, I can get that information on here without having to have an engineer attend which would be wasting their time as he isnt going to fit for about a year or so! I guess he wants to save up!

[chiller man]

Hello b2s.A 256 sq mtr conservatory is a big begger, and you can bet it aint a lean to design. the roof will have hips and valleys so getting the overall volume will be a challange. Why use a total loss system (DOORS OPEN). If the sun stikes a polycarb or glass roof, even in winter, the temp will rocket. Ive seen cons climb to 90f in December after 20mins of poor sun.The only way to reduce the temp economicaly is air change rate. Fit an arrangment of roof vents, and plenty of opening windows,it works I Know, Ive got one.



PS , Most conservatory sales people will tell you what you want to hear. What they dont tell you is you will have to shell out another 5k to sit in it in any comfort during summer time. Best thing to do is sit in the ROLLS on the drive with the A/C on if it gets too HOT!!!!! CONSEVATORIES ARE DESIGNED TO GET HOT.

[back2space]

Hello b2s.A 256 sq mtr conservatory is a big begger, and you can bet it aint a lean to design. the roof will have hips and valleys so getting the overall volume will be a challange. Why use a total loss system (DOORS OPEN). If the sun stikes a polycarb or glass roof, even in winter, the temp will rocket. Ive seen cons climb to 90f in December after 20mins of poor sun.The only way to reduce the temp economicaly is air change rate. Fit an arrangment of roof vents, and plenty of opening windows,it works I Know, Ive got one.



PS , Most conservatory sales people will tell you what you want to hear. What they dont tell you is you will have to shell out another 5k to sit in it in any comfort during summer time. Best thing to do is sit in the ROLLS on the drive with the A/C on if it gets too HOT!!!!! CONSEVATORIES ARE DESIGNED TO GET HOT.

Yes in winter its not a prob as the conservatory doors into the house are flung open and it heats the ground floor and lounge etc so a nice bonus but with trees being around it doesnt get that hot in winter in their as the sun is low in the sky so the conversatory doesnt get directly hit due to position of trees etc.

It can be the opposite in their in winter as in last year we was at 3C in there one day was freezing and couldnt use the room.

[chiller man]

Hi b2s. point taken regarding the trees. I still think its a stinker though,Its a big building,i would still go for fans and plenty of openers though, but if not ,oversize the plant, conservatory temp swings are cronic,good luck mate.

[back2space]

Thanks Chiller Man.

We have tried the fans approach, doesnt work its just like sitting in front of a fan heater when there on. If we have all the windows and doors open he ends up with wasps and bees and other insects flying around inside and then getting stuck on the windows.

I think its mainly for heating he wants the a./c as this I know will be cheaper than running electric underfloor heating and quicker response times too.

[eggs]

chiller man / b2s......

I think you two are talking about two different conservatories.
b2s- chiller man thinks the conservatory is 256m2 ie 16m x 16m (which is what you said)
chillerman- the conservatory is app 4m x 4m.

Carry on.......

Cheers

eggs

[back2space]

chiller man / b2s......

I think you two are talking about two different conservatories.
b2s- chiller man thinks the conservatory is 256m2 ie 16m x 16m (which is what you said)
chillerman- the conservatory is app 4m x 4m.

Carry on.......

Cheers

eggs

Oh theres been some confusion.

Its 16m2 which the total floor area etc.

4 x 4mtr as you say.

Cheers eggs.

[monkey spanners]

Air con Haiku

Sun heats blinds,
blinds becomes radiant heater,
space warms up...

[paul_h]

...b2s wants a 3.5Kw for this?
double brick single window 4x4m^2 room would be fine with that.
But what is the wall type, window/glass area and ceiling height of a conservatory?

[back2space]

...b2s wants a 3.5Kw for this?
double brick single window 4x4m^2 room would be fine with that.
But what is the wall type, window/glass area and ceiling height of a conservatory?

That was rough measurements, the conservatory is joined onto the house the only wall area is a dwarf wall about 2.5ft in height.

The ceiling gently slopes up to join the side of the house and ranges between 7-8.5ft in height.

The rest of it is double glazed windows and the conservatory gets the sun in the morning then again near the end of the evening so its not in the sun all day.

Bearing in mind though the width of it is little more than a set of double doors with a window on each side of the double doors.

The unit is primarily used for heating they will throw the doors open in summer and it cools down very quickly and there is also a ceiling fan which they use.

My friend has said the only time it will be used for cooling is if its late on an evening and they have shut the doors to keep the moths out or its raining etc.

The unit chosen outputs 4kw of heat and upto 3.7kw of cooling should it be needed.

They were using a 3kw fan heater in there last year which did the job perfectly however very expensively!