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-   -   Installing A/C in old house - Conventional vs. High Velocity (http://www.diychatroom.com/f17/installing-c-old-house-conventional-vs-high-velocity-135765/)

alisanke 03-03-2012 07:49 AM

Installing A/C in old house - Conventional vs. High Velocity
 
I need advice regarding two options to retrofit air conditioner in our 80 year old house (no existing ducts). Here's a bit about our house - 2200 sq ft, 3 bedrooms and office on 2nd floor, half attic space is a finished bedroom and half is unfinished (plan to leave it this way), basement is unfinished (we'd like to make a game room there in the future).

1) two conventional systems - one coming from the attic for 2nd and 3rd floor and one coming from the basement for 1st floor

2) one high velocity system - coming from attic to 2nd and 3rd floor and then through 2nd floor closets to the 1st floor

Price wise the 2nd option is 2K more (that's not a big deal if it means a much better solution). Our concerns include the following:

a) noise level inside the house
b) noise coming from outside units
c) size of outside units since we are thinking of hiding them behind our bushes in the front yard
d) electricity (we have 100 amps service) 5) risk of poor install leading to terrible problems down the line
e) look in our house, how it will fit with our old radiators / hardwood floors / original house details
f) we like the idea of two zones with conventional

Worth noting is that we've also considered mini split units but ruled them out already for a number of reasons.

Thanks in advance for all your advice!

joecaption 03-03-2012 10:23 AM

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.

hvac5646 03-03-2012 10:41 AM

Quote:

Originally Posted by joecaption (Post 869061)
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.

joecaption 03-03-2012 10:58 AM

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.

alisanke 03-03-2012 11:30 AM

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!

joecaption 03-03-2012 12:02 PM

http://www.energystar.gov/index.cfm?...sulation_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.

alisanke 03-03-2012 12:39 PM

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

hvac5646 03-03-2012 01:35 PM

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.

alisanke 03-03-2012 03:10 PM

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

mpnret 03-03-2012 03:29 PM

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.

alisanke 03-04-2012 08:58 AM

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?

alisanke 03-04-2012 09:27 AM

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?

Code05 03-04-2012 09:34 AM

Quote:

Originally Posted by mpnret (Post 869328)
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.

yuri 03-04-2012 10:15 AM

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

hvac5646 03-04-2012 10:21 AM

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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