Don't go adding ducts without understanding the impaceon the rest of
your system. A return duct in the kitchen sounds like a great way to
get kitchen odors spread throughout the house. In some jurisdictions it
is against the building code.
In the toe kick space, like most installs.
> I see the only place for it
> is to move it higher above top cabinets. I also plan to add a couple of
more
> ducts and probably one return duct.
Which would violate code for return air!
> Again the only place I see for those
> additional ducts is in the walls above top cabinets. I cannot put them
into
> ceiling because of ceiling joists. Any advise would be appreciated.
Call a professional and get it done correctly.
kjpro
Should be all jurisdictions, as it's in the IMC.
kjpro
Putting toe space grills in houses with A/C and a basement or
crawlspace can be a mistake. Normally, the duct is attached to the
floor under the cabinet under the cabinet. This pressurizes the space
under the cabinet with cold air. The subfloor under the cabinet
assumes supply air temperature. If there is any humidity in the
crawlspace or basement, moisture will condense on the underside of the
subfloor. Conditions are then ripe for mold growth or wood rot. Even
if you duct the air all the way to the grille, there can still be
problems. The floor in front of the grille will also approach the
supply air temperatures. About 10 percent of my business involves
fixing problems with damp crawlspaces. The biggest problems are with
houses with toespace grilles Avoid toe space grilles unless you are in
a very dry climate.
Stretch
Your plan is workable, especially since you are adding other
supply ducts... you may want to eliminate the return duct
though as that will take cooking odors all through the house..
you want the kitchen exhaust to take those outside as a rule.
and you want the new supply air to move in a way that it does
not interfere with the kitchen or stove top exhaust ..that
means no supply air blowing on or around the stove top.
The supply air registers above the cabinets should ideally be
in a facia flush with the front of the cabinets and be rated
for wall placement, as contrasted to say ceiling registers
that are configured differently.
The air should not just be dumped in a space atop the
cabinets.
However adding more ducts could unbalance the system and
deprive other parts of the house of air, so that the kitchen
would run too cold in the summer and too hot in the winter.
To cure that put manual balancing dampers in the kitchen ducts
so you can 'balance' the system later. If you rely on the
supply air grill dampers you could get whistling. or you can
do it as planned and see how it operates ..then add balancing
dampers as required later.
There are thermostatically controlled dampers you can buy but
thats a lot of complexity for a slight gain in your situation.
Phil Scott
Mech engr. HVAC contractor
>
>
First, if I do it, it's ducted all the way to the grill.
Second, I live in an area where humidity isn't an issue.
Your thinking, and sharing your knowledge, that's good.
That's the nice thing about the NG, it's made up of people from all
different areas of knowledge.
kjpro
"Phil Scott" <philsc...@sf.sbcglobal.net> wrote in message
news:Hp5Zd.18002$Pz7....@newssvr13.news.prodigy.com...
if you have only 2" or so above the cabinets you might have to
use 'slot diffusers'. take a sketch to your local sheet metal
shop and see what they say.. it shouldnt be a problem... or
they will have a source. Or call your local HVAC wholesaler
and tell them you are a home owner looking for wall slot
diffusers...however long but narrow...whatever space you have.
OR
In your case I might build a sheet metal box behind the facia,
flange it to the facia on the inside and cut 1/4"lots in the
facia with a router. or dado blade in a skill saw.
Phil Scott
Solve the humidity problem in the crawl! Then don't worry about problems
with the toe kick supply.
Greg
We lived in the desert where COOLING was much more important than heating.
Our kitchen ducts were placed above the cabinets..Picture cool air
'falling'.
We were on a concrete slab so actually all the ductwork was "above" the
living space. It sounds like you could add a run from the existing duct,
up and along the tops of the cabinets and box it in with a bulkhead from
cabinet tops to ceiling. I like to do that anyway when I build..finishes it
off neater than just having the upper cabinets hanging on the wall and a
dusty, clutter collecting "shelf"/tops above.