Building Code for energy conservation: One thing leads to another

Energy code

Remember back in the 1970’s, even into the 80’s, when houses were always built with 2 X 4 wall studs? The first NYS Energy Conservation Code was introduced back in the 1980’s.

Changing to 2 X 6 studs had nothing to do with structural requirements, it was all about providing more insulation.

When the Energy Code kicked in the minimum R-value required was R-21.

The easiest way to comply was to use 2 X 6 studs. Conventional fiberglass batt insulation is 5.5 inches thick and provides an R-value of 19.

Then, the sheathing, siding and interior sheetrock was counted by adding the extra couple of “R” to get to 21.

There are other ways to obtain an R-21 in the walls, without building with 2 X 4 studs.

The use of a high R, foil faced rigid foam board became popular and remains a fairly common product today.

This is applied to either the inside under the sheetrock or outside under the siding.

Either way, the overall thickness of the wall assembly is thicker than just a 2 X 4 wall with plywood and sheetrock.

A benefit of using foam board sheathing under the siding is the “continuous” concept, covering all the studs thus providing the thermal break at each stud.

Today a very popular method of insulation is spray foam.

Today’s spray foam products are much better than some of the first widely used variety of spray in place products of the 1980’s.

Shrinkage or settling was a common problem then. If the spray foam shrinks inside the wall cavity it can quickly create cold air infiltration throughout the wall system, totally defeating the quality of the job.

And to correct the problem is a nightmare. Shrinkage today is virtually unheard of… if properly applied.

The proper application of spray foam has proven to be extremely effective in complying with the Energy Code.

It seals the walls, ceilings and/or roof assemblies against air infiltration and provides about 7-R per inch.

The joints between exterior plywood sheathing [wall or roof] are common places for air infiltration.

The use of house wrap applied to the outside walls, under the siding, became popular as well in the 1980’s.

This is still widely used today. Another very good product, if properly applied.

This is an air infiltration barrier, not a moisture barrier.

Current Energy Codes require tighter and more insulated methods in both residential and commercial construction.

As buildings get tighter and more insulated, air infiltration is less and less.

As windows and doors are made and installed better, then sealed in placed to prevent air infiltration and combined with sealed exterior wall and roof assemblies, interior environments are getting less and less air exchange, or outside fresh air.

This creates a different problem of having stagnant air inside. One thing leads to another.

The new Energy Codes that are coming out require houses to be tested for air infiltration, commonly known as the ‘blower door test’. That’s right contractors, get ready… the blower door test.

This will need to be done by a qualified third party person. It’s actually in the code now, and has been for a while.

Just like other required inspections like electrical, plumbing, framing, the blower door test will become the norm.

Because buildings are now getting tighter and creating new problems [lack of interior air exchange] air exchange and heat recovery systems will become much more popular.

Again, one thing leads to another. All these things apply to all new construction, even additions and most renovations.

Hopefully the payback is lowered fuel usage, thus cost savings and more comfortable buildings.

On the national level, less fuel usage means fewer emissions into the atmosphere, which is the true underlying reason for the Energy Codes.

It wasn’t so people could save money, that’s the bonus.

But it all comes at a cost up front, which ultimately falls on the consumer. A qualified designer can help calculate the payback.

What happened to the day when if you heated your house with firewood, you were exempt from the Energy Code?

Gone… that disappeared several years ago. No matter how you heat a home now, wood, wind, electric, fuel oil, propane, geothermal, solar… they all require compliance to the Energy Code.

No more exemptions for buildings heated with renewable energy sources.

Knowledge of the code, and understanding why… may or may not make sense.

However it is all intended to be for the better in the long run.