I’m going to be building a 2000 ft2 house on the B.C. coast just north of Seattle. Hoping to make it tighter than skin on a weiner. If I use a Heat Pump for cooling and heating does that take care of my fresh air ventilation concerns? thanks
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Tool Donations Sought
I'm matching tool donors to a church mission to Haiti - we're shipping a bus converted to a medical facility in January (we hope) and can fill it with clothes, tools and all sorts of stuff needed in that poorest of all countries. A few hand tools or power tools can provide a livelihood for an otherwise destitute family. Please email me if you have tools to donate.
Thanks to Jeff and David and Jim and Rich and Steven and MArk for their offers!
The list keeps growing
At the moment, we're looking at shipping the stuff in February, 2004
Sleepy, Bob?
Tall him about HRV systems.
Dave
Sleepy? Naw, I just wanted to sate my position succinctly (for once {G})
I don't have a working knowledge of HRV systems. we don't use them around here, so I figured better for someone else with working experience to talk about them.
FWIW, in MI, (at least SE Mi) they are now requiring what are essentially barametric dampers on a fresh air supply connected to the return duct work (the name of the most commonly used is escaping me at the moment) to ensure ventilation and, I believe, as a guard against excessive negative pressure in the combustion zone.
_______________________
Tool Donations Sought
I'm matching tool donors to a church mission to Haiti - we're shipping a bus converted to a medical facility in January (we hope) and can fill it with clothes, tools and all sorts of stuff needed in that poorest of all countries. A few hand tools or power tools can provide a livelihood for an otherwise destitute family. Please email me if you have tools to donate.
Thanks to Jeff and David and Jim and Rich and Steven and MArk for their offers!
The list keeps growing
At the moment, we're looking at shipping the stuff in February, 2004
Ok, I'll give it a go. My HVAC experience is commercial, so the other guys here can jump in any time.
He is going to use a heat pump, so that may indicates that he is not using a combustion appliance. If that is the case he still needs to control his indoor air quality. This includes humidity and air filtration. The HRV (heat recovery ventilation) is designed to aid in both of those areas.
A really tight home needs a source of fresh air. In commercial building this referred to as makeup air, and is set by most codes as a minimum of 10% outside air. That rule does not as yet apply to residential systems to my knowledge. It would probably wastefull from an energy conservation point anyway.
An HRV is connected to the return air side of an air handler. It will exhaust a small percentage of the circulating air in the house to the outside, and replace it with fresh outside air. The heat recovery takes place in a heat exchanger that takes as much heat from the conditioned air leaving the house as possible, and adds it to the outside air that it is bringing in. I am unsure of the efficiency of the systems, but it seems to be the better than simply exhausting and replacing conditioned air.
Depending on the unit and design criteria, it is my understanding that many can be connected to or replace the normal exhuast fans you would find in todays new homes. They then serve as humidity source controls as well as aiding in the prevention of the "sick house" syndrone that is often associated with the "super tight house."
His HVAC contractor should be able to calculate the design loads for his house and include an HRV system in the equipment specifications.
I am in much the same situation. My new house is designed with a ground source heat pump aiding the passive solar design, and two wood burning stoves. My HVAC contractor and design archy/enrgy engineer both specified an HRV for the house.
Agian I am not an HVAC guy, so the gurus of this area can jump any here and make whatever corrections, additions, and explanations they feel are needed.
Dave
Are you interested in meeting a specific code requirement or in creating a quality environment for you and your family?
Code requirements can be met, in most jurisdictions down south in the US, by a minimum of operable windows. The International Mechanical Code 2000 calls for 0.35 ACH (air changes per hour) which, with 8 ft ceilings, would mean you need 94 cfm of outside air to meet the minimum.
94 cfm will result in approximately 3800 btuh of additional total cooling load and 8700 btuh of additional heating load, if untempered. This at worst case conditions where I live. Not enough really to bother with energy or heat recovery.
On the hand, if you are interested in creating a better than average environment or have specific requirements to meet, there is more to consider. You have to define the requirements and criteria for your application and needs. At 1.0 ACH (a minimum recommended air turnover rate for general air quality in a residence) you would need about 270 cfm of OA and that would probably not work well with a simple system. In this case an HRV would be recommended.
Tim