I am frequently asked two questions about our house:

1 – Would you build this way again?
2 – Is there anything you would change?

The answer is a resounding, “Yes!”  While I was hoping for even lower utility bills, in comparison to my next door neighbor, we are indeed saving a significant amount of energy (and cost).  Even with their R19 (stick and batt) walls with an extra wrap of R1.5 foam (which is better than local code), our utility costs are at least $2000 LOWER per year than theirs are.  I can only imagine what a house this size, built with R11 2x4 walls, would cost to heat and cool.

In all honesty, I believe this building is even better than the utility bills show.  In fact, I have been able to locate the largest “energy vampires” in the house, unfortunately I am powerless to eradicate them.  Those energy sucking beasts are called – children. :)

They frequently leave lights on (especially in closets where lights may stay on for days), televisions playing, video games paused, and computers on, despite repeated reminders not to do so.  They never seem to verify the refrigerator or freezer door is closed properly.  They go in and out of the house frequently and often leave doors partially or completely open.  The oldest one spends enough time in the shower to use all the solar hot water made during the day.  Then, there is the endless supply of laundry.

The cool/funny/neat thing is... our energy bills are still significantly lower than our neighbors, and they have three adults.

2 – Is there anything you would change?

Yes.

1 - If I were to do it all again, I would rethink the GSHP system(s).  Not that I would go to any other form of heating/cooling, but I would re-engineer the entire system.  As it stands now, I would eliminate the desuperheaters from the geothermal (GSHP) units and use the money saved to add another panel to the solar hot water system.  I have no scientific data, but it is pretty easy to see the water tank primarily heated by the GSHP never gets hot despite near 100F outside temperatures and 68F inside temperatures.  While these conditions should be ideal for generating hot water with the desuperheaters, we make very little.

Our GSHP systems are clearly oversized, run infrequently, and therefore make little hot water.  Perhaps if the system was smaller it would run more often and make more hot water.  The questions is, is it better to run a large unit less frequently, or run a smaller unit more often?  I just don’t know.

Next, given the size of the units, we could have done without the expense of adding stage 3.  Stage 3 consists of electric resistance coils and some heavy duty (and expensive) electrical work.  In fact, the breakers for the electric resistance heat have never been turned on.  This would have saved us enough to add one or two more solar hot water panels.

My load calculations were always significantly lower than the ones received from the “experts,” but there is little I can do about it now but caution readers.  Do the math to justify the size of the GSHP system and the cost of adding the 3rd stage and desuperheater.  Even with the high efficiencies of the GSHP, I think it is very difficult to beat the efficiency of a good solar hot water system.

2 – I would have fought harder to get a high efficiency wood burning fireplace/stove.  We (my wife) chose the convenience of propane and an on/off switch, over lugging cordwood and ashes.  Propane is expensive to use (so we rarely use the fireplace), and one good sized log in a high efficiency fireplace would have heated the entire house nicely.

3 – In hindsight, I would have liked to have designed in an airlock entrance for the front door.  Despite having one for the mudroom, the front door is used much more often.  When designing your house, carefully consider which entrances will be used the most and plan an airlock entrance there.  My wife insisted on having a mud room but she rarely uses that entrance either.  You have been warned. ;)

4 – Use methods to isolate the energy recovery ventilator (ERV) from the house.  Use isolation dampers for mounting, and flexible couplings to connect the ductwork.  While we are used to it now, there is a constant hum from the unit.

Ed