Energy Savings that Are Hot Air! : why doesn't this surprise me? The brits are able to do the real calculations, but we aren't. This article is the first of many to come about the savings that doesn't exist!

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Hi Tom, it is a can of worms for sure, everything from incentives that encourage contractors to exaggerate to meet a minimum % improvement, to home owners who simply want to enjoy their new warmer homes. 

And then there is the "one at a time" savings claims.  A new furnace will save you "X" dollars, but that is assuming the house is still poorly insulated.  Cut the heat loss in half and the saving for the new furnace will be cut in half as well.

Advertising has always been subject to puffing, inflated promotions intended to sell a product or service.  But when they in turn want home owners to finance a huge bundle of improvements and all of the puffing comes to light, meaning the savings don't come close to paying for the loan, it hurts everyone, except maybe the contractors and mfgs who are long gone. 

Between energy costs stabilizing or dropping, government funding running dry, and now indications that home owners are not saving what they expected or were promised, energy efficiency is becoming a tougher market and it is a shame, because it didn't need to be this way.


The things that really save energy aren't being done nearly enough. Air sealing and fixing ductwork/airflow issues in HVAC systems. You never see rebates being offered for the things that make the biggest difference.

Mass Save has a pretty aggressive program addressing both those issues Bob

Glad to see somebody is addressing the real issues. Mandating minimum SEER/AFUE isn't what reduces demand.

This is a thermal model run of 400-minutes, 20C delta-T between a standard wall and the same wall with 1-1/2" insulation board added below the siding with 1/2" furring to allow condensation to drip down and increases thermal resistance 3-4 times by greatly reducing conduction. When using hemp-lime of 1-1/4" it adds thermal mass as well as some insulation so work even better but uncommon yet available and can be applied using gunite equipment.

The Brits are doing the same thing we are which is the issue - if you do X you will get Y based on generic predictions (or should we say the best case result received). Oh wait not every house is a worst case, so the actual results are Z which is the issue the Brits are facing as they measured the results - oh crap...

Well duh, that is why most programs, sales people, etc... have a big trust issue. We sell that every house is unique, it is its own system, but then we use generic global numbers like they will magically work for every house & set of occupants. Shoot I know one program that turned into nothing but an HVAC rebate program as replacing "any" HVAC system with a "high efficiency" one automatically tripped the magical "20%" reduction number - no manual J's or anything else needed... so every time a unit broke down, well we can upgrade your 13 SEER with this here 15+ SEER (it might have been 18 but I don't think it was & still the numbers wouldn't have worked) unit & oh you will also get this rebate... 

Oh & Tom many of us can you get you legitimate numbers & do calculations, but there are other factors that can influence them like the occupants, actual weather, lack of maintenance, etc... Of course for many people it really isn't about savings, it is about ones comfort & health

For wood-frame residential the easiest way to improve things is under floors remove the batting, add in pipes with water for thermal mass and duct heat by them on the way to the room and insulate below the joists to close it off.

How you collect or create the heat or cold has options, without the thermal-mass you can't store therms so it takes more inputs per day to keep the room comfy, and it costs money to not have the thermal-mass in the system.

In a home with ductwork it changes the purpose of the duct to a floor vent and instead the duct feeds the floor joist spaces and the exhaust from them goes out the vent into the room.

Making an exterior upgrade lengthens the time between inputs by changing the wall into thermal-mass for the inside along with reducing conduction, an important distinction of why it works so well; also quiets the room and both of these upgrades don't disrupt the residents while they are done.

hello tom,

thank you, i've enjoyed your ivory tower comments, they certainly prepare you to be an editor! however, for the rest of us who live in glorified caves which need constant work & inputs of capital just to keep running, may i comment?:

no one exists who is going to spend the money to do a hydronic 1st floor retrofit, as you suggest!

thermal mass is a big negative in a home which is not passive solar that uses ductwork to heat and cool! thermal mass acts like a sponge for energy, not what you want when you have the advantage of home air ductwork to make rapid changes in temperature!*

exterior upgrades happen infrequently due to their immense cost & the small likelihood of finding a contractor, anywhere, at any price who is capable of following instructions. also, you do not want thermal mass installed except in the example, maybe, of a trombe wall on the correct side of a passive solar home.

it was recently reported again that U.S. homes are becoming too airtight which is causing radon induced lung cancer rates to rise, again. the obvious solution is to crack the windows, which i did immediately, install a radon system, which i have in client homes, & install an erv, which most clients will not pay for!

*oversizing of hvac has traditionally been employed by hvac contractors for two reasons: quick temperature changes, & more profit selling the larger unit! it is impossible to stop contractors from this practice.

Tom, some of my building experiences were to design and build passive-solar beginning in the 80's so have no clue what you're talking about, when you do that you learn what thermal-mass can be from a pile of rocks to an aquarium in the sunny spot of a room, how to use it and what it costs to retrofit compared to supplying heat every time the building overheats or cools down too much.

I never built an ivory tower but for my first season as an apprentice carpenter we built 22 small 2-story cabins.

You have choices, either use thermal-mass of some type or run a heater-cooler to adjust more often!

As you say that's what industry wants you to do and the homeowners I talk to don't want any part of that pay-by-the-watt scene, sorry but that's reality Tom and your statement, "thermal mass acts like a sponge for energy" shows you're not too clear on how thermal-mass fits into the equations, you don't need a trombe wall or anything like it, you just need a heat source to circulate to the thermal-mass and from there into rooms, how that's done is only limited by cleverness in design.

Passive-solar is mainly for new design, these recommendations are to use active-solar instead because the home wasn't built with passive-solar in mind and many lots don't offer a good line-of-sight to sunlight very well in winter for walls but most any building has roofs with sections that do heat up quite often. If both those aren't available a separate collector on the lot is feasible to gain the heat.

I'm for reducing the need for external thermal inputs so to cut down or eliminate using electricity or burning something to keep a building in the comfort zone from having the thermal-mass experience to see what it does and the solar collection schemes whether passive or active to design something that fits the circumstance.

That's rather easy to do and not expensive for remodels and none of these interrupt the people living in the space, interior walls are left alone.

Compared to the fuel-energy costs of having no thermal-mass and allowing conduction tied to standard wall design the remodel will pay off in less than 3-years or nobody will do it nowadays, this is doable when thermal-mass is added along with active solar-thermal from some source. And, you don't need to remodel the whole house, only the walls for rooms that need improvements for a tight budget.

For thermal gain, it's simple to use a section of roof as the "heater" whenever it's hot enough to store that heat until tomorrow below the floor instead of building a greenhouse addition or adding that much collection some other way. So payback is saved energy bills versus capital investments in the remodel, the math works out positive on that over time in every case, if it's too long a payback the people won't do it.

By collecting and storing heat it doesn't matter if a home is sealed well or not, the bills will be far less in direct proportion to the heat gained and stored for the daily cycle. Doing the floor thermal-mass and sealing that back up reduces radon worries as you can vent the crawl spaces to the outdoors without affecting keeping the home warm.

Every homeowner I've talked to so far on this is interested, my work right now is gathering the data, from data loggers & weather station & solar gain data that can be taken onsite to plug into thermal software to be more precise on estimates of needs to get the results to show to prospective homeowners. And, I have a tiny home design on the way to be built this season. Once the numbers are from data, it'll be a different ballgame and I expect to be hammered with orders.

Glad I could entertain you Tom, and good luck to you!

Well, if you read the link carefully you'll learn that only ONE of the Brits speaks the truth. The rest, like most institutions here flogging energy conservation, are prone to gross exaggeration.

The savings DO exist, but not in the amounts claimed.

I work with a small federal funded grant that is working to promote home energy efficiency in rural southeast North Carolina.     I really appreciate the discussions on HomeEnergy Pros on this matter of  reliable information on energy savings that come from major upgrades to homes.
Most the programs designed to improve energy efficiency in homes are being done in urban areas, and in areas of the northeast and western USA.  There are very few model  programs that have been done in rural areas of the southeast.  We have had very little comparative information to build upon on energy usage in detached single family homes in rural areas of North and South Carolina.  
We have gathered information over the past two years to help build knowledge understanding, and practice in this area.  A recent study on the “Help My House Pilot Program” in rural areas of South Carolina has provided a lot of very useful information that can be very helpful to us to establish comparable benchmarks of home energy use in a rural area very similar to ours in home design and home energy use, in best practices for recruiting clients in a rural area, and for projections of energy to be saved by specific measures.  This program also provides detailed information on cost of specific home energy upgrades.
I encourage you to do a GOOGLE search for this program and look at the results which are presented in layman's terms.
I know that the work we do in improving energy efficiency in buildings is frustrating.  However, I can see that our work is making a major positive impact on the US economy. 
I do believe that we can retrofit America and create a lot of jobs and save a lot of money. 
I do believe that:

Innovations in energy efficiency in housing and buildings and retrofits to improve energy efficiency and improve sustainability are growing at a faster pace than housing starts and new construction in general.

The work you do in this area is having a major positive impact on the US economy.  Keep it up, please.


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