HVAC Sizing in a house with open/ cathedral ceiling

[edwardh1]

I got kicked off the HVAC - talk forum for asking this question.

What procedure is used on houses - say a two story - where there are several open areas from first floor up to the second floor, in sizing two HVAC units- say heat pumps??? one on ground floor one on 2nd floor

The answer I got was "your HVAC pro will know how to do it?

Anyone else??.

[kdog]

a/c sizing is most definitely an art!! many things must be considered as heat loads,secure yourself a copy of the book titled "modern refrigeration" and study up on it as effects such as windows,exposure direction,materials used in the home,not to mention age/condition and how well sealed it is. there are no pat answers for sizing,but in the window shaker world,we work by this general rule of thumb- 400 sq ft per ton (12,000 btu/hr) of refrigeration. there are some pretty sophisticated systems around now,including split systems and heat pumps and geothermal,your best bet is to call in a reputable pro who is well experienced at these things(such as a trane rep) as sizing and system design/balance is one of the most important steps to making a sound decision(cheaper is NOT always better) remember you only have one chance to get it right........ do they still use such thing as a sling phsychrometer?

[applianceman18007260692]

12000 btu for every bedroom is a good rule of thumb

 

[edwardh1]

I wonder how manual J addresses the open floor plans?