Brian Gaff (Sofa) wrote:
Noisy?
I would imagine if we go down the reversible heat pump route, then some
kind of air moving system is going to be needed again?
Brian


Yes, a hot air furnace has an air handler. With
a motor. It makes a noise.

Years ago, before the air handler was introduced,
they did make hot air furnaces that worked by
convection. They are quiet. But, they also have
their own sins.

The house across the street back home was heated
that way. Convection heating.

The oil furnace in the basement (i.e. good combustion temp)
has a huge flared pipe on the top. On the first floor is a
floor grate. It was maybe five or six feet in diameter.

You could feel a steady flow of warm air out of that pipe
while the furnace was operating. But the airflow is also
in the wrong place, because it's in the center of the house.
The walls are cold. You also need an opening into the
second floor, so that sets the plan for how the second
floor is laid out. You can't close the bedroom doors up
there, or no warm air will get into the bedrooms.

The air handler solves this problem. It doesn't rely on the
generous nature of convection air movement. It has the power
to move the warm air where it is needed. The noise,
what little there is, is the price you pay for that
solution.

With the air handler, I can have the warm air rise along
the exterior walls, reducing the "cold wall effect". And in
principle, with good design execution, I can even warm areas
which are an extreme distance from the furnace. With the
old convection furnace solution, standing on the grate
"was a good time", sitting in an upstairs bedroom, not
so much.

Our old church had the convection heating. It had
something like three 130,000 BTU furnaces. And big grates
in the floor for the heat to rise. And considering the
size of the church (and my poor memory of the specs),
I think that system did an excellent job, because
there were no barriers to air movement. If the air
was stratified in there, you didn't notice it. But those
furnaces also used a lot of oil, and the church wardens
were constantly complaining about the expense. They
couldn't possibly afford to use oil for that today.
The church wasn't exactly R2000, so it's not a surprise
it took thousands a month in heat. All the glass on the
place was single-glaze. I doubt the walls had much in
the way of insulation. You'd think Satan would keep
the place warm, but the church was designed to keep
Satan out.

Paul