Building Performance

Tools for building performance.  Like a car takes fuel and maintenance to travel distances, a house requires these to maintain a comfortable home conditions within.  Miles per gallon (mpg), expected car life, and estimated lifetime repair costs let one compare the performance of cars.  How about house performance?

Assessing house performance gets involved.  In existing houses we do not always know precisely what we have, particularly with regard to thermal insulation.  Yet we measure passive air-leakage of a building, and we can correlate energy use to outdoor temperature and related weather conditions.  We then rely on models of known relationships to implicitly reveal where energy is being wasted, and guesstimate (make estimations based on informed guesses) the potential return on investment for building improvements.  Statements about what improvements pay for themselves all make assumptions.  Our buildings being 100 years old, implies many things about how our buildings were constructed and the probability of damage and rot from past events.

Most of MSCs energy goes to produce and pump or blow heat.  Replacing refrigerators is easier than retrofitting a house.  But the energy embodied in our houses is too substantial to throw away for recycle unless future maintaining air quality, regulating temperature, and repairing the building can all be reduced by building modification.

The fastest way to loose heat is a hole in the wall.  The greater the temperature difference, the faster we transfer heat.  These may be permanent holes like a chimney, exhaust duct, and gaps between structural parts of the house.  These may be opened windows to respond to overheating and air-quality issues from poorly thought out kitchen and heating system design. To seal a house tighter without considering conditions and resident responses wastes money because systems fight one another.  Similarly many modern buildings fight themselves by operating forced cooling and heating systems simultaneously and not considering passive heat and humidity flows.

After drafty holes in the wall, Windows are an obvious source of passive comfort or discomfort that residents have control over.  Per area of a houses shell windows deserve profound attention.  However, they are likewise profoundly expensive to the point that only recently have windows performed sufficiently well that replacing rather than repairing old windows can pay for itself (depending on how much you pay, and how well it is installed).  Walls are simple enough for a simple Resistance to heat transfer to approximate performance. As with air-leakage, heat escapes fastest through the least resistant path.  In a smart modern home, windows will be that path because permanent holes are minimized.

What are windows wort consideration:

Cheapest improvement:

$9 for a box of window film for multiple windows that can remain up for multiple years.  This is disposable, yet very hard to beat in financial return.

Refurbish old window.  This gets complicated because a very careful and skilled resident can do wonders with $15 of gaskets and caulk and supplies on hand yet finding and affording hours for such skilled and careful labor costs.

Deep Refurbishment/restoration/upgrades.

   Storm window inserts

   Exterior storm improvements

   Replace pulley systems with spring track systems and insulate wall cavities.  Involves cutting down old sashes which A-Craft Windows will do.  ~$170/window + foam canisters --if volunteer install labor is free

   Unless we will increase wall insulation above R15 this may be all that makes sense to do. Repair-ability is vital to keep maintenance costs down.

New Window

   New window insert

   >$300 Re-framing costs extra, but might allow 1 window to replace 2 to 4 for fewer window/install charges and greater energy efficiency (fewer moving & joined parts to leak...).  Assume vinyl windows last 10 to 15 years before performance permanently deteriorates.

   Now we are talking window quality.  The more we pay for quality windows, the less one can risk cheap labor resulting in flawed installation craft.

   Sturdier windows with 3 glass panes require sturdy construction to support them.

Who makes repairable, "R5" windows (U≤0.20) ?

   Marvin Windows in MN... has made "R5" compliant U≤0.20 windows, but no indication of "PHI compliant" capability U≤0.14.

   H-Window in WI makes Nordic Doors and triple pane Windows   <-- We have not confirmed U≤0.20 "R5" nor U≤ 0.14 "PHI compliant" but these look well crafted.

   PEAK Building Products carries OPTWIN Windows   <--  PHI certified.  These U-values appear high because of metric units, a different standard window, and component by component measures.  Wood with Al clad is repairable, durable, and efficient.