The Great Ventilation Debate Rages On

The best minds in the building science field have not been able to yet agree on a ventilation rate for residential buildings.  The Energy Vanguard Blog is the best spot to witness that ongoing debate.

In my view, setting a standard for the ventilation rate is completely the wrong approach.  

As an analogy, consider the heating temperature control for a house.  If the temperature drops below a user-defined comfort setpoint, then heat is added to the space.  That's very simple, easy, cheap, and effective. Thermostatic control of  space heating can hardly be improved upon.  Why does it work so well?  Because it MEASURES, then CONTROLS.

In space heating, what we DON'T do is add a fixed number of btus per hour to the space during the winter season.  Yet that is what the ASHRAE or BSC ventilation standards propose to do*.  The current "cfm/person" approach is pseudoscience and should be abandoned in favor of  measurement and control.

What should we measure?  We're not sure yet, but if cost were no object, we would measure CO, CO2, methane, humidity, radon, and VOCs.  We may find one of these that can be a proxy for some of the others.

With that "air quality control" in place, the occupant can dial in a preferred setting, then forget about it.  The house will then get only what it needs, and there will be no money wasted on over-ventilation.

Ah, but we can't trust air-quality-ignorant occupants to know the best setting, right?  No, we can't, because many of the airborne contaminants cannot be detected by human sensory systems.  There is an obvious solution to that also, just ensure that the controls have scientifically derived maximum concentration settings for each contaminant.  Back to the space heating analogy:  thermostats have a minimum setting of 45F because bad things (freezing pipes) can happen below that setting.

*A standard ventilation rate can't account for all the variables.  Consider this:  what if the outdoor air is actually worse than the indoor air?  In that case, ventilation is the wrong answer, and a smart control would shut off the ventilation.

Living with Car2Go

Let's say you have a net zero energy home.  That's great.

But if you are still driving 20,000 miles a year, you are using way more energy than a carless person living in an old, energy-hog house.  So in order to live truly sustainably, you have to think outside of your box.

Cities are very energy efficient places to live, mainly because you can walk, ride a bike, or drive a very short distance for most things in your life.  Two of the most annoying things about living in a city are traffic, and finding a parking spot at your destination.  Therefore, city living becomes more enjoyable if you can live without a car.  As cities become more dense, cities must find ways to help their residents wean off of cars.

Real estate in cities is just too valuable to use for storing cars and for providing wide streets.  Since we only use our cars for 1-5% of the day, why are we paying to insure and store them the rest of the time?  Car2Go isn't a perfect solution yet, but it's an extremely convenient and successful way to help us share our cars and reduce the number of cars we need to store in the city.

Claire Martin of the Denver Post wrote a great article that describes the reality of using Car2Go, RTD and BikeShare rather than owning a car.

Nearly Everything to Know About Building Green

Martin Holladay's list of articles is very complete, and the comments section is also extremely helpful:
http://www.greenbuildingadvisor.com/blogs/dept/musings/how-do-everything

This list is continually updated, which is good, since the field is always changing.

GreenbuildinginDenver aims to fill in the blanks for Colorado's Front Range, and add topics where our expertise is helpful.

Check it often for the most unbiased and accurate methods to save energy in residential design and construction.

Pin Foundations: A Very Green Foundation System

Here is a very  inexpensive and non-invasive foundation system that is slowly gaining popularity.  What is holding it back is typically conservative builders and structural engineers.

http://www.pinfoundations.com/green.htm

If your jurisdiction requires a soil report, then you may be able to find a geotechnical engineer who can work with the engineers at Pin Foundations and get the structural plans stamped.

The floor insulation and moisture vapor control details are important:  http://www.pinfoundations.com/docs/DP%20SKIRT%20WALL%20PRL%20TO%20JOISTS.pdf

In most cases, this system means:
1.  No excavation contractor
2.  No poured footings
3.  No concrete forming or stemwalls
4.  No concrete delivery trucks using diesel and disposing of waste concrete

Since the system eliminates conventional concrete work, many would consider it very green.  Concrete work is still tolerated by most green builders due to its durability and longevity, but the concrete industry is apparently one of the top contributors to global warming.

LED Bulbs Are Now as Efficient as Fluorescent Tubes

They are affordable too.   This bulb currently cranks out 80 lumens per watt for under $11:
http://www.amazon.com/G7-Power-G7A19W10-Omni-Directional-Dimmable/dp/B00AN1OQMO/ref=pd_cp_hi_3

But next year there will be better ones.

Saving Water and Floorspace

Maybe you've seen those toilets that save water by incorporating the handwashing sink into the lid of the toilet

There is also a way to retrofit a sink to the top of most side flush toilets for $140:

I like this idea, because I think you could save room in a house by putting the toilet and a shower in a smaller than normal bathroom, and have the main bath sink hovering in the bedroom as IKEA suggested in last year's catalog.   This reduces collisions between the two people sharing a three piece bath.  Saving water by reusing it is good too.

Also, some may criticize this toilet-top-hand-washing idea because there is no hot water available.  Well, most people don't wait for hot water at a conventional bath sink anyway.

Car2Go is Free Until August 4th

Now You Can Go Carless Painlessly - -

You've probably already seen the blue and white Smart Cars sitting all over town with keys in the ignition. Once you've signed up, you can take any of them for a few minutes or across town and then leave it anywhere in Denver. No reservation needed.  Your smart phone instantly shows you where the closest one is.

For longer trips, sign up for E-Go CarShare, but you have to return it to their special spot.

This means that you can design your garage to store your stuff, and you don't need to pretend that your car will use it.