# Installing A/C in old house - Conventional vs. High Velocity



## joecaption (Nov 30, 2011)

Why did you rule out the mini splits?
They would able able to address most of your concerns with your install.
I have one that I can not even hear running, uses about 1/3 the power of a reguler unit.
There's going to be a lot of work trying to hide all the duct work.


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## hvac5646 (May 1, 2011)

joecaption said:


> Why did you rule out the mini splits?
> They would able able to address most of your concerns with your install.
> I have one that I can not even hear running, uses about 1/3 the power of a reguler unit.
> There's going to be a lot of work trying to hide all the duct work.


Mini-splits take away from the charm of the architecture...makes the home look like an experiment ....

Old homes deserve TLC because they are the heritage of the neighborhood and the country.

'Nuff said.

You favorite is a good choice, but the hi-speed system would be be less invasive as only small opening in ceiling are required with a central return for each system.
You will need to to increase the service capacity...100 amps won't cut it.


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## joecaption (Nov 30, 2011)

Not trying to disagree, but I've seen them with the ducts hidden in the crown mouding with just a small round hole and LG makes one with a flat panel that you can put a picture on.

Were not there to see what the OP has to work around, but all of the 100 plus year old houses I've worked on that had retrofitted HVAC systems added had duct work running running everywhere exposed that had to be covered up to hide it.

When he said only 100 amps. that was my first thought. Old wiring, under sized wires. 
Possible lack of insulation in the walls. Some of the many joys of owning an old house.

I'm not a HVAC guy by any stretch, just sharing what I have seen before dozens of times.


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## alisanke (Mar 3, 2012)

Thank you for these suggestions. Yes, I am concerned about 100 amp and would rather not mess with upgrading service. Any other thoughts on this?

The house is brick. No insulation in walls or basement. 

It is not really an open floor plan, so mini split is not ideal. And more importantly, would reduce the charm of the house. We are in an upscale historic neighborhood and need to be mindful of the resale value. 

Thanks again!


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## joecaption (Nov 30, 2011)

http://www.energystar.gov/index.cfm?c=home_sealing.hm_improvement_insulation_table

Is there any empty slots avalible in your breaker box?
What are you using for hot water, cooking stove, heat.
Some of the fine elec. guys on here will need that info when making some suggestions.
Also going back and editing your profile so they know where you live will help.


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## alisanke (Mar 3, 2012)

We are in Boston. Our hot water and heat is gas. Dryer, stove, oven are electric. Thank you.


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## hvac5646 (May 1, 2011)

I don't see any way around the service up-grade...your box is at, if not already, at capacity with the usual things, add the appliances I don't see any room left for two systems..

Sure doubt you are going to to get a second system powered off so small a load center.


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## alisanke (Mar 3, 2012)

Yes, the panel is full. We were going to add a subpanel but hope to not do service upgrade.


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## mpnret (Nov 11, 2010)

I just looked in my electric panel. A/C compressor = 40a, A/C air handler = 20a, dryer = 30a, electric range = 40a. I'm thinking your going to need lots of candles or everything of yours is smaller than mine.


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## alisanke (Mar 3, 2012)

Thank you. I cross posted my 100 amp problem in electric forum.

Assuming I figure out how to deal with electricity, any other thought regarding whether conventional or high velocity is better suited for my needs?


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## alisanke (Mar 3, 2012)

Thank you. I cross posted my 100 amp problem in electric forum.

Assuming I figure out how to deal with electricity, any other thought regarding whether conventional or high velocity is better suited for my needs?


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## Code05 (May 24, 2009)

mpnret said:


> I just looked in my electric panel. A/C compressor = 40a, A/C air handler = 20a, dryer = 30a, electric range = 40a. I'm thinking your going to need lots of candles or everything of yours is smaller than mine.


You do not add up breakers to do a load calculation.


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## yuri (Nov 29, 2008)

You will definetly need a service upgrade and a highly trained and experienced company to do a PROPER load calculation to size your cooling needs and do the install. I just watched a marketplace special last night and they have thousands of new condos in Toronto, Ontario and some are having HUGE problems with high velocity systems not being sized, installed, setup properly and not cooling or heating properly etc. Mostly because very few contractors understand them and know how to do them properly. How you find one I do not know. Best to talk to lots of your neighbors and see what they did. I would vote for the minisplits especially the Fujitsus which are like the Lexus of the industry. They have inverter ecm compressors and SEER ratings up to 21 and are literally so quiet you cannot hear them run. I believe they have flat panels like the other guys and are quite cosmetic. There are LOTS of generic minisplit brands out there and hackers installing them so I would do LOTS of research as to the contractor and his reputation and stay with Fujitsu or LG or Mitsubishi as they are well known and been around for a long time.

http://www.fujitsugeneral.com/end_user_home.htm


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## hvac5646 (May 1, 2011)

Mini splits in a historical America home is like putting a a prom dress on Richard Simmons....it just don't look right (but Richard might still like it):no:


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## yuri (Nov 29, 2008)

Nothing is easy in those homes but at the end of the day a choice has to be made. A skilled contractor who specializes and does renos in those homes is the best way to go. We have one here who does 1/2 to million $$ renos and the experience and proper subcontractors to properly do the finishing which is usually the biggest problem when you start cutting into those old lathe and plaster and architectural ceilings etc. VERY expensive proposition to say the least.


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## mpnret (Nov 11, 2010)

Code05 said:


> You do not add up breakers to do a load calculation.


Obviously. I am just throwing out some breaker sizes here and you can guess at the operating current for a very general approximation. There is a lot more to be taken into consideration here. I am just not used to seeing 100 amp service with central A/C, elect dryer, elect range plus the general stuff. At least he doesn’t have an electric hot water heater. Too bad he doesn’t have gas cooking or dryer. That could make this a go assuming everything is average. Again, no substitute for a true load calc.


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## hvac5646 (May 1, 2011)

OP, code five was working with what we can tell from the info provided.

It is an honest assessment of your electrical supply which everyone agrees need to be up-graded.

Your reluctance to accept the suggestion does not alter the need to change the electrical service.

You have a full box and even though an electrical load has not been done I think you will find the local authority not too willing to accept two sub panels.


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## hvac5646 (May 1, 2011)

OP, code five was working with what we can tell from the info provided.

It is an honest assessment of your electrical supply which everyone agrees need to be up-graded.

Your reluctance to accept the suggestion does not alter the need to change the electrical service.

You have a full box and even though an electrical load has not been done I think you will find the local authority not too willing to accept two sub panels


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## yuri (Nov 29, 2008)

Probably still has that creepy old cotton covered wire too. I am amazed more of those homes don't burn down. You don't want to be moving it or disturbing it to add subpanels so I would get some info from a reputable electrician on what is the safest way to go about it. Fuses are verbotten where I am and the ins companies won't insure some homes with them or charge twice as much.


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## alisanke (Mar 3, 2012)

Thanks everyone. I understand that there is concensus for upgrading to 200 amp service.


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## Missouri Bound (Apr 9, 2011)

High velocity systems, when installed correctly can be nearly invisible. Keeping the detail of the home, that is probably the way to go.


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## yuri (Nov 29, 2008)

alisanke said:


> Thanks everyone. I understand that there is concensus for upgrading to 200 amp service.


With these character homes you DON'T want to be shopping for the cheapest contractor. The better ones won't hack holes or do cosmetic damage etc so you get what you pay for. Also these modern minisplits and other units are very grounding and neutral sensitive so an electrical upgrade helps with grounding etc and is safer overall.


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## yuri (Nov 29, 2008)

Missouri Bound said:


> High velocity systems, when installed correctly can be nearly invisible. Keeping the detail of the home, that is probably the way to go.


The best and ONLY way to know 4 sure what you are getting is to see and hear one installed in your neighbors house AND get their contractor. Otherwise it is a lottery as to what you get and you don't want to gamble with a character home.:no:


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## Ironlight (Apr 13, 2011)

From my perspective it really comes down to the cost of maintenance of two systems vs. the convenience of two zones. That said, in general you're probably going to keep your thermostat at a consistent temperature and a well designed and balanced system will give you even cooling throughout, so you might want to consider carefully whether two zones have any real practical benefit for you.

I would probably go with high velocity in an older, historic building for the simple fact that your ducting will be less obtrusive. That is very popular around here in older town homes for exactly that reason.

The one downside about high velocity from people who have it is the noise of the air coming out of the vents. It bothers some people...other people not at all.


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## beenthere (Oct 11, 2008)

mpnret said:


> Obviously. I am just throwing out some breaker sizes here and you can guess at the operating current for a very general approximation. There is a lot more to be taken into consideration here. I am just not used to seeing 100 amp service with central A/C, elect dryer, elect range plus the general stuff. At least he doesn’t have an electric hot water heater. Too bad he doesn’t have gas cooking or dryer. That could make this a go assuming everything is average. Again, no substitute for a true load calc.


100 amp service is all I have. 

Central A/C
Electric range
Electric dryer
Electric water heater


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## COLDIRON (Mar 15, 2009)

Go with the mini splits you'll be happy. An old house is nothing but problems besides your house isn't going to be a museum or art gallery it's just an old house. Plus if you have a failure you always have another one for backup until the service company can get to you.


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## hvac5646 (May 1, 2011)

Mini-Splits are not the answer.

They do nothing but detract from the historic persona the home projects.

You either get or you don't. This is one type of job where what seems like the "best or easy solution"--- mini split ----is not good for the home.


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## alisanke (Mar 3, 2012)

As I mentioned, we ruled out mini splits. Although I know we don't live in a history museum we still need to be mindful of our resale value of the house and enjoy the charecter it projects. Mini splits are great in a modern decor, but that's not our house.

It seems to me high velocity is a more risky solution since it has to be done 'just right'.


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## hvac5646 (May 1, 2011)

did u try getting a recommendation for a guy from the historical society?

hi pressure ac's have bee installed successfully and noiselessly for years

u could call the factory to get a name too.


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## Missouri Bound (Apr 9, 2011)

hvac5646 said:


> did u try getting a recommendation for a guy from the historical society?
> 
> hi pressure ac's have bee installed successfully and noiselessly for years
> 
> u could call the factory to get a name too.


I have to agree. I was in an old historic church for a wedding a few years ago and they used the high velocity system for both heat and cool. During the ceremony it was quiet as most weddings are and when the air conditioning came on you could see motion on the fabric in the building but absolutely no noise. Properly designed and installed systems are very quiet.


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## mpnret (Nov 11, 2010)

beenthere said:


> 100 amp service is all I have.
> 
> Central A/C
> Electric range
> ...


No lights?


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## Missouri Bound (Apr 9, 2011)

SpacePak| Air Conditioning SpacePak Mini-Duct SpacePak High Velocity Info

I would look here.:yes:


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## hvac5646 (May 1, 2011)

my vote is for spac pak.


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## yuri (Nov 29, 2008)

Good link and they have an install video too. Freon lines still need to be run on the outside of the house etc and they are not cosmetic either. Looks like a good system IF installed properly.


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## beenthere (Oct 11, 2008)

mpnret said:


> No lights?


Candle lights. ROFL


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## hvac5646 (May 1, 2011)

Been is a Quaker. His TV is a candle in a box..only gets one channel:thumbsup:


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## beenthere (Oct 11, 2008)

hvac5646 said:


> Been is a Quaker. His TV is a candle in a box..only gets one channel:thumbsup:


LOL. Right now, I'm down 3 computers. I normally have 5 on almost all the time.

Lost the hard drive on 2 of them, and the power supply on the third.


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## yuri (Nov 29, 2008)

hvac5646 said:


> Been is a Quaker. His TV is a candle in a box..only gets one channel:thumbsup:


Is that one of these guys?:laughing:


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## alisanke (Mar 3, 2012)

Thank you all for your advice regarding my AC options. We decided to install conventional on 2nd and 3rd floor with unit in attic. We might wait to do the 1st floor until we remodel the kitchen and swap out electric for gas stove /oven. 
One debate we have now is regarding whether we should keep our cast iron radiators or go with hydro-air. Any thoughts on this?


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## beenthere (Oct 11, 2008)

Hydro air won't be as comfortable as your cast iron rads.


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