As a consumer, this might come as a shock to you but Building Codes in North America are based on limiting probabilities; and products and assemblies related to those probabilities are defined around the lowest allowable government regulated standard before a municipal building inspector is obligated to fail it. It is under these objectives that State and Provincial Codes including the National Building Code of Canada (NBC) address:
health and safety
accessibility for persons with disabilities
fire and structural protection of buildings
Even though there are health statements addressing inadequate thermal comfort, specifically air and surface temperatures in the NBC appendix (see below) - the Code does not specifically address ALL of the required elements necessary for human thermal comfort.
Because I'm an old guy with a long history in the industry I can say with 99% accuracy that in North America as in the UK, 72°F (22°C) air temperature is treated in isolation with thermal comfort as if two were synonymous terms -even though the knowledge bank of comfort includes numerous other elements studied formally with decades of on-going scientific research in human physiology and psychology.
The results of exhaustive studies are found published today in industry developed thermal comfort standards which state;
"It is intended that all of the criteria in this standard be applied together since comfort in the indoor environment is complex and responds to the interaction of all of the factors that are addressed."
Translation: air temperature alone does not
define comfort conditions, nor does
heating, ventilation and air conditioning (HVAC) equal
indoor environmental quality.
Before you obtain a building permit, be informed that the above quote is from the globally recognized ANSI/ASHRAE Standard 55 which at this time can only be voluntarily adopted as its scope and purpose exceeds the minimum objectives of most if not all Codes related to residential construction. Even the top brand names in housing programs such as Energy Star, LEED, R-2000 still do not reference the Standard even though it serves as a indoor environmental cornerstone in designing spaces occupied by humans.
Keep reading it gets better...
So yes - it's true about codes and the minimum benchmark...and as a member of the public you can test this yourself by asking your potential architect, builder and his/her HVAC sub trades for improvements to building and mechanical systems to meet the voluntary Standard and watch how they respond...the first thing they'll say is "what Standard?", in which case you the consumer will now have to explain it to them, to which they'll respond with, "ooh...that will be an upgrade".
Understand - if improvements "up" to industry developed thermal comfort standards are considered the "upgrade", then everything below the industry standard should in our opinion be considered a "downgrade" - yes I said a downgrade; and once you learn this stuff you too should consider built to code systems as the downgrade. For those with chronic comfort problems, you have literally and likely paid and are continuing to pay too much for the downgrade.
If you don't want to do the "upgrade/downgrade" experiment with your soon to be construction partners, then here's some actual statements, for example, from the most current version of the National Building Code of Canada(NBC);
"The NBC establishes minimum measures..."
"...it's requirements can be considered as the minimum..."
"no more than the minimum"
and the following direct statement from the National Building Code (NBC) is very useful for consumers unaware that codes are not a guarantee of performance to your individual and subjective needs,
"The design of a technically sound building depends upon many factors beyond simple compliance with building regulations."
Please read the last bullet again...it is not a trivial statement and it's very important for your understanding of what it takes a professional, to actually provide thermal comfort in spaces for someone like you - especially when you as a consumer have likely been conditioned by industry to accept the minimum "built to code" HVAC system is the benchmark in acceptable performance.
Here's the thing...regardless of what you may have or will be told by others...past research shows approximately 40% to 50% of home owners are not happy with their indoor environments for a number of reasons - one of which is intimately tied to thermal comfort.(see note 1)
Here's more that you should know...
Is there a place for Thermal Comfort Standards in Residential Construction?
Many argue that there is no place for thermal comfort standards in residential construction which I and industry colleagues find rather short-sighted as do consumers who are presently dealing with thermal comfort issues. Regardless of our opinions, Codes referencing ASHRAE Standards including, "ANSI/ASHRAE 62.2-2004 Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings" will find guidance in Section 2.1 which states, “This standard considers chemical, physical, and biological contaminants that can affect air quality. Thermal comfort requirements are not included in this standard (see ANSI/ASHRAE Standard 55-2004, Thermal Environmental Conditions for Human Occupancy).”
As far as the authoritative ANSI/ASHRAE 62.2 residential ventilation and air quality standard goes, the thermal comfort standard should be consulted in residential construction - full stop.
Built to Code HVAC Budgets
On a macro scale, subject to regional corrections, the "built to code" HVAC budget allowance will range between 3% and 5% of construction costs. You need to interpret this as, "my 'built to code' budget will get me the minimum grade HVAC system before an inspector is obligated to fail it". Even then, you can still have a "built to code" system but the installed quality of the "built to code" system can partially destroy the value of your home (see W5 Investigation "Cold Comfort for Consumers" or "Doc Zone: The Condo Games").
Now some contractors will recoil at this - I can guarantee it - just like I can guarantee the 'recoilers' can't list the ten elements of thermal comfort and just like I can guarantee they don't own the thermal comfort standards. But as we noted in Part I, all you have to do is visit the numerous online HVAC forums and talk to the consumer advocacy groups and better mechanical contractors fixing systems to see what consumers are presently dealing with when it comes to their thermal comfort (see list of professional trade associations).
Please also understand, there are also many very good reputable builders and HVAC contractors presently delivering environments which exceed the standards but realize they are likely not doing it for "built to code" prices.
If nothing else, recognize if building codes and builder budgets for HVAC were judged by educational standards - then your "built to code" HVAC system would earn a grade of D - the minimum. If you find the price of a Grade D product is too high...imagine what happens to the outcome of your Grade D HVAC system should you and everyone else try to negotiate for a lower price? That would be driving the system towards something less than D...you with the street smarts - you can figure out where that goes (see adjacent photo, courtesy of Allison Bailes, III, Ph.D., Energy Vanguard).
I really feel for the better contractors and Code inspectors who have to operate under this caustic system of driving indoor environmental health related system to the "D" grade or lower.
We can tell you...it'll take a different set of design skills, someone versed in indoor climate engineering and building and health sciences; and it will take more time, and will need better trades, equipment and systems.
Most importantly it will take the willingness of the builder and his service providers and suppliers to work with the specialist so that you get - not what is based on Codes - but what is based on your personal subjective needs.
Finally, if someone on a fixed "built to code" budget believes they can get Grade A HVAC for Grade D prices all we can say is good luck. The past decade has driven every business related to construction to the lowest profit margins ever, and at a time when the fat in business processes have long ago evaporated. Simply put - if a construction related business today isn't running lean and mean it is not in business or its a start up...and if the start up or existing business is actually delivering Grade A systems at Grade D prices it won't be in business for long simply because there are insufficient profits to sustain the operation.
When it comes to "built to code HVAC" it's not what you paid for that'll get you...it will be what you didn't pay for that'll drive you crazy.
With the exception of high performance homes such as or comparable to EQuilibrium™ or PassivHaus, there is simply no way around it - all of the proceeding dialogue translates to a required larger share of the construction budget for Grade A indoor climate systems. If you want an efficient system that can establish a healthy environment you are simply going to have to make the building enclosure, natural low VOC materials and HVAC system a priority over size and bling.
In closing on lesson one...even though you can't see it, this part of invisible architecture trumps everything else because;
It affects the health of the indoor environment and by association your physical and mental health, the health of your family and health of the relationships you have with people in your home.
It affects the monthly utility operating cost of the home and by association your financial cash flow.
It affects the integrity of musical instruments, heirlooms, paintings, furniture and finishes and by association the value of these types of assets.
and if matters at all to you,
It affects global energy and environmental sustainability.
We don't know how we can be any clearer...if you
are building, buying or renovating a home you as an educated
person can not pretend to be ignorant of what " built to code"
means when it comes to thermal comfort (and
other elements of IEQ).