Re: Inflatable HVAC duct valves

[Marc F Hult <MFHult@xxxxxxxxxxxxxxxxxxxxx>]

On Sat, 10 Dec 2005 13:13:23 -0500, "E. Lee Dickinson"
<lee@xxxxxxxxxxxxxxxxxxxxx> wrote in message
<dnf5tp$2js$1@xxxxxxxxxxxxxxxxx>:

> ...[]  but I have developed a deep and abiding
>hatrid of drywall work. So that's a last resort for me!
>
>I'll dig around ebay. Thanks.

Have you tried your hand at plaster-on-lath ? Horsehair on brick? *Much*
more challenging ;-)

More seriously, what did you do to determine that your furnace blower can
handle the increased back pressure that is developed when you close off
ducts/outlets?

I ask because one of our furnaces died this week (2 days after its annual
$90 inspection/tuneup ;-( so I am in the process of rethinking that part of
the HVAC system.

Seems  to me that the new variable-speed, DC blowers could handle variable
back pressure more easily than legacy 1-speed, AC blowers.

With the recent rise in natural gas prices in my locale, the cost of
electricity for residential heating became about 10% lower than natural gas
(assuming 90% efficiency) so a major redesign may be in order.

When I ask the local HVAC contractors about zoning the system, they tend to
group into those who respond with a look of near panic and those with that
'ca-$ching' grin ...

... Marc
Marc_F_Hult
www.ECOntrol.org