Mechanical

Air Conditioning

Trane-dx-cooling-unit

We broke down and asked Bob to go ahead and put in a conventional air conditioner last week.  The house was doing very well considering the heat wave we’ve had, but when the temp climbs over 95 degrees for over two weeks straight, and topping out at 100, it gets uncomfortable!

Fortunately, we had budgeted a high-efficiency DX cooling unit, and Bob has worked installation into his schedule.  If we get our photovoltaic panel array at some point, I guess we can feel a little better about using the energy for powering this thing.

At 90 degrees and under, the combination of good cross ventilation and ceiling fans in every room is fine, so most of our summer we will be leaving it off.  I’m not a fan of conventional air conditioning, because in my experience, it results in closed up buildings where no one interacts with the outdoors.  With our indoor/outdoor patios, we will see if we can keep a good balance...    

Furnace

 SClarkson-Furnace

Bob put in our furnace last week.  We spent some time analyzing the heating and cooling loads to size the unit properly.  Considering we have very well insulated walls and roof, plus triple pane glazing, the unit can be smaller than typically used for a house of 2500 square feet.

This is a Trane 95% high-efficiency unit with a two stage variable speed fan, so we hope to see some significant savings on energy usage (especially when combined with our tankless water heater).

Note:  Again, we see this as the next best thing to radiant floors which were out of our price range.

Plumbing-Mechanical Rough-In

SClarkson-plumbing

The mechanical and plumbing sub-contractors have been working on the rough-ins.  It’s amazing how much abuse the studs and floor joists can take with all the holes and drilling -- and still perform!

We have specified a number of interior chases (exterior SIPs walls don’t really work for this) which are quickly filling up.  

Mechanical Ideas

 1441SClarkson-current-mech

1441SClarkson-current-mech

Since we had to forgo the radiant floor system, we’ve had to get serious about what we will be using for a forced-air mechanical system. We will be using a high-efficiency furnace (90% or better). Instead of using the “rule of thumb” type sizing, the more thorough “right sizing” or “Manual J” method will be used. In addition, we will hopefully add third party testing - blower door and duct leakage.

We are still on the fence about using the traditional compressor-based air conditioning unit (granted it would be high-efficiency - 15 SEER) or go for an efficient indirect swamp cooler. The trouble is we haven’t found a cost efficient method for combining these two very different systems.

For domestic hot water, we will be using a gas fired tankless water heater (on-demand). I think we will start with just one for the entire house, and probably rough-in for a second, considering we are also prepping for a future guest suite on the basement level.

Tough Decisions

 Money symbol

We’ve been reviewing our bids for the last few weeks -- a challenging and frustrating process. Materials and building costs do not seem to reflect any economic downturn.

The price points of a number of items that we researched and would purchase directly are also towards the upper end of what we can afford, so some trimming will be done there too.

Ultimately the biggest item on the chopping block seems to be radiant floors. It’s amazing that these systems are so expensive. It’s been around for a while now, but unfortunately, it has not become a commodity item like conventional forced-air systems.

With energy conservation in mind, we are looking at a high efficiency furnace, a swamp cooler rather than a conventional compressor (central air) type air conditioner, and an on-demand type water heater.

We shall see...