Category Archives: DER

The Conversation Continues!

My last posting as part of the ongoing Deep Energy Retrofit #DER conversation regarded a definition of DER.  I made the argument for using a threshold of 30% savings. The specific conversation is in regard to historic homes. There have been several Bloggers involved in this conversation and others reading. You may read my first post HERE.

Sean at SLS Construction has a post that he is maintaining as a startingpoint and links to updates in the conversation. John at Birmingham Pointe is the Preservationist among us? He actually owns and restores these treasures of times past! Peter Troast of Energy Circle has been involved!

Most recently Sean posted some definitions about Historic, home ownership and compliance width various agency requirements!  After reflecting on the discussion It is time for me to pick up the pen for the next post!

During an energy audit of a existing home, I see any number of things related to the efficient use of energy. As I make my list of observations for further examination, I have learned to keep several parameters up front. These would be, in no specific order, Budget, desired outcome, safety, durability, and comfort. I also find it Imperative to remember that I am not in charge, the homeowner is in charge.

There are a number things that I routinely run into during an audit, that are not the most energy efficient. Some are predictable because of the construction techniques used during construction, or the type of construction, or the era in which it was built. Is the house timber framed? Wood stud? Brick clad? Is the house a craftsmen style from the early years of the 20th Century? Masonry Block? Post WWII tract type? Each of these have unique features as well as common improvements that relatively small changes will save some insignificant amounts of Energy. The improvement I can see and model may seem like a no brainier to me, but to the homeowner it becomes almost an insurmountable problem.

One of my first audits was a 1960 ranch with full basement. The homeowner is a young couple and he works construction. Their goal was to get plan of work for him to complete during his down time on the winter. One of the fastest returns for their money was to put some insulation on the basement walls. No problem with blowing into the finished walls. When the recommendation also included 3 inches in the storage areas on the bare walls, my easy to install efficient improvement ran right into the homeowners impression that giving up 3 inches of storage would be a major problem!

Anyone working in the energy improvement field must keep in mind: You must meet the needs and perceptions of the homeowner or nothing happens!  You can have the best ‘fancy dan’ plan with all sorts of neat figures , printouts and scientific backup, if you don’t meet the homeowners need, your plan is worthless.

Another audit was a very large home, 2 story, full basement, 3 bedrooms, 6500 sf!  I spent a full day on this audit. Presented the plan over 2 hours, and another 4 hours in follow up field work. The comfort concern was the 2nd floor rooms on each end of the home were hot in the summer and cold in the winter.  I fixed up a ‘fancy dan’ plan for him. Dropped his $6,400 annual energy bills to $3,200.  Solved his comfort problem with a recommendation to increase the return air in the effected rooms.  Estimated cost for the additional returns was $200.00

He cherry picked the added attic insulation, because he could see the problems.  He did it fast, and soon.  It met his real need which I finally discovered on the 4th visit.  He really didn’t think his energy bills were that high.

Therefore, anyone wishing to complete a DER for a home, must have the Home Owners Approval, and that approval meets the perceived needs of the homeowner – it will not necessarily meet the perceived needs of the ‘Energy Guy’ writing the plan.  You should think of this as “Rule #1”, when all else fails remember Rule #1.








The Second Point of this post is about the Deep in a DER.  Deep Energy Retrofits should meet some type of savings across the board.  The Twitterverse lit up last night when @EnergyVanguard was Tweeted for people to give him a percentage.

Let’s look at Retrofit.

The implication is certainly not a rebuild, or a gut rehab. That would involve taking most of not all the exterior walls back to the studs or other type of internal framework and then rebuilding. If a DER was a Rebuild or a Gut Rehab, why would it be called a Retrofit.

Could you substitute reduction for retrofit? – Yes.  What about rework? Remodel?  Restore? All of those work for me.  They also all imply that the work is more of an improvement to the structure instead of a rebuilding of the structure.

Now that the “R” in DER has been established as improving as opposed to rebuilding, we can move on.  “E” of course is Energy.  Which leaves “Deep”.

Asking how deep is deep reminds me of the wood turning question about gouges:  “How sharp is sharp?”  We have established some limits on Deep.

We know the structure is not going to be rebuilt, we know the structure is not going to have major removal of visible material, only for the purpose of installing energy efficient components, such as insulation.

We also can use ‘Deep’ as meaning not shallow.  Therefore Deep must involve a plan of systematic improvements that total to deep.  This plan will only be implemented as the home owner has the money/time/desires.  This may be over a period of years.  If a deep plan cannot take place over a longer period of time, then I must send you back to read  ‘Rule #1’!

So, deep means more than doing one or two things. It means having a plan.  A plan of improvements that can be phased over a period of years, if need be. A DER would not just involve equipment change out or windows, as most sales types would lead you to believe.  And deep doesn’t mean rebuild.  It therefore falls in the middle.

In the middle means a 50% maximum reduction.  Not being a one or two item improvement plan also means that it should be at least 30% reduction.  Which leaves reduction in what.

We are talking about historic homes.  These homes have history and therefore we know what the energy costs are.  The reduction must be calculated from historical that applies to that home.  Trying to bring in code becomes an exercise in futility.  We have already ruled out rebuilding. We also need to remember ‘Rule #1”.  How does this work out.

If we start with a home built in 1800, with a historical usage of $5,000 annual energy usage, what are we talking about in reductions of usage?  30% would end with a $3,500 annual usage, and 50% would be $2,500.  If you look at a reduction from code, then you introduce an additional step.  You first have to arrive at a code usage; then make the reduction.  So, if the code usage on this home comes in at $3,200, we have range of $1,700 – $2,250; if the code usage comes in at $4,000 the range would be $2,000 – $2,800.

That means we define our DER as:

  • A 30% or more reduction in usage compared to historical.
  • It means the DER is a plan that uses the concept of the ‘House is a System’. It must address the construction of the actual structure. It cannot just consist of generalities. Timberframe is different from Balloon Framing which is different from a 50 year old American Suburban ranch.
  • It allows various parts of the plan to be implemented in phases.
  • And last, but really first – we acknowledge ‘Rule #1’. The home owner is in charge.


A Twitter Conversation – Moving Along, Part 2

Previous Info on the Conversation

OK!  Since I posted Thursday night, things are moving.  People are talking to each other and it is becoming evident that a few more are involved that were not listed originally.  Also, not being from Derby, CT – where they have 200 – 300 year old houses, with much historical value to preserve – I am finding that I don’t know as much as I thought – or that I don’t know how to apply what I do know.

Additional Players that have been brought forth are:

  • Martin Holladay:  In the Twitterverse he is known as the Energy Nerd.  His blog is full of interesting stories and tidbits of knowledge.
  • Carl Seville:  His blog and in Twitterverse he is the Green Curmudgeon. He has his own outlook on all things Green and brings a wealth of info to the table from his experience as a builder.
  • Then there is JB.  Hailing all of us from Baltimore, JB is in construction and remodeling.  Since Baltimore has been around since before the night when ‘Whose broad stripes and bright stars thru the perilous fight,’ was observed and recorded; they, like Derby, CT have some of those 200 – 300 year old homes to work with!  JB has a blog,  Building Moxie.

Welcome to the > 140 Convo.

Since Thursday

John P.  left a comment on Sean’s Blog Post regarding some of his concerns.

  • The stereotype carried by some that DER requires extreme measures.
  • Not destroying historic fabric
  • Reversible
  • The concept of ‘the house is a system’ means that houses built 300 years ago, may work well as their own system, but when a new construction method for current housing is introduced, then the law of unintended consequences intervenes.
  • Work on Energy Efficiency should be staged and completed over a number of phases and years.

He also discussed the definition of ‘Deep’, countering my proposed use of the Wiki definition at 30% reduction. John offered some additional criteria. Primarily he is proposing to include climate in the definition of Deep.

Updating the Conversation

I want to pose some questions and try to clarify where we are going and where we need to go. I also want to respond to John’s ideas on refining the definition of Deep.

John’s first point was stereotypes.  That is my word, and I chose it specifically because when people deal with what they assume about another they are creating a stereotype. I believe the best way to deal with those is to get to know the other person or position and thus my participation in this conversation.

The second point he makes is not destroying the Historic Fabric of the home.   I can agree to this one.  I don’t like changing the looks of a home, just to improve energy efficiency.

  1. It is usually not cost effective.
  2. It can become a distraction from the original intent.
  3. If you don’t like the looks of an old historic property, what are you doing working on one?

I believe his third and fourth points are inter-related.  If you cause a problem with a change in how the home works, you need to be able to undo the change.  Therefore, changing the exterior, by removing siding to install rigid foam insulation and then re-installing the original siding might be reversible. That would depend on how you treated the windows and doors due to the increased thickness of the walls.  In the end, I think most of these types of improvements will not be cost effective in energy savings.

In my first post is had a couple of points that I believe must be kept in mind.

Significant Savings from the improvements

  • Savings from improvements are probably best considered significant over a 15 – 25 year period. At the end of that time, a different property owner may be present, new methods of improvements may be available, increased prices of energy make a revision of the cost effectiveness calculations essential.

Work that is Safety Related may not have a dollar savings.

  • How do you calculate the savings in replacing Knob and tube wiring with modern wiring?
  • What about reductions in water presence anywhere in the building that it is not designed to be? What about comfort of the building occupants? When people are uncomfortable, they do many things. Electric resistance space heaters are expensive to operate and are unsafe.
  • Other items related to Building Code issues.

Defining a Deep Energy Retrofit. #DER

The closest I have worked to one of Derby, CT’s older houses is a 92 year old home in Wichita.  I wrote about that audit and the following upgrades in ‘What Good is an Energy Audit?’  The cost effectiveness I think should considered is illustrated here by the proposed improvement to the uninsulated walls. It took 99 years. Doing it for less would have involved drilling the brick exterior and leaving an obvious patch.

With the exception of the exposed insulation on the basement walls and weatherstripping on one door, none of the energy efficient improvements were visible. The total cost of  improvements will be returned to the homeowner in 14 years, assuming no increase in electric or natural gas rates.

In percentage terms, this plan mets the definition of 30% or more. If you look at energy cost reduction, it figures at 36%; if you look at peak power reduction (summer) it is 41%; if you look at CarbonDioxide reduction it is 34%.

The insulation contractor on this project was Northstar Comfort Systems. @Nstarcomfort They did a good job, the home owner is very pleased and the project verification was achieved on the first visit.

John has suggested adding climate into the definition of deep. I think it is already there.  If you moved this house from Wichita to Maine, the pre-improvment costs would be higher, due to weather and cost of energy. Weather is obvious, cost of electricity in KS is about 10 cents per KWH and in Maine about 17 cents.  The reduction in use of BTU would be at least what it was here in Wichita.

I don’t think climate needs to be added because it is already there. The idea of savings has to be based on what the house is already spending.  Weather is part of that calculation.

I think a simple percentage is adequate to define Deep. It works, it accounts for all variables and it follows the KISS principle. It works for several different metrics, dollars, BTU or your favorite energy measure, or environmental like carbon.

Comfort and Safety

I think the ideas of safety should be self evident and I would also include durability in them.  If a home is aged in centuries, it must have been durable.  If a home is aged in decades, it must have been durable. It is up to every homeowner to continue to maintain and improve on durability.  That is why we look at a new roof or repainting our homes periodically.

Comfort is a different issue, that really doesn’t have a price tag. I have found that people living in a home they think is uncomfortable do many things to obtain comfort. They continually adjust the thermostat, they add electric space heaters, or window air conditioners.  These are expensive. They sell the home and then the next owner can be uncomfortable.

The first example of comfort came when I was doing my due diligence in starting my career in Energy Efficiency. I attended a seminar at a local home show on Energy Efficiency. The presenter related one of his experiences with comfort instead of purely cost reductions.

He had done some duct leakage testing in his own home and found the duct leakage was a major contributor to the cold bedroom of his daughter.  This led to an easy fix of sealing the accessible duct work. For this example, I would thank Jeff Boone @JFBoone of Northstar Comfort Systems.

Information I Need

John points out a, new to me take, on the house is a system. Building Science has always considered the house to be one system. If you change an item, something else will probably change.  The corollary to this is ‘First, do no harm!’. If you make or recommend a change, you should look at what else may change and take steps to ensure the reactions to your first change are positive for the house and the occupants, not negative. Examples would include:

  • Adding insulation to one side or the other of an exterior wall could change how the wall dries. That change could cause mold and decrease the quality of indoor air quality.
  • Doing air sealing work can make significant energy savings. Decreasing the ventilation through infiltration could create a dangerous situation, if the decreased amount of fresh air will not support the needs of the hot water heater and furnace.

John expands on this by adding the concept that a house as a system can be specific to a type of construction. A house built with techniques in common use in 1800 would have the system effected if the improvement used some technique that is in common use today. This is something I need to know more about.

  • How different do the original construction techniques need to be for this to become significant?
  • Is it something that that only happens in a 200 year swing of construction techniques?
  • Is it something that occurs in applying today’s techniques to a ballon framed Victorian?


The goal of this post was to advance the conversation #DER with some basis and examples of the proposed definition of Deep and to set out that energy efficiency improvements are never a goal in and of themselves.

It is not a good idea to do an improvement that will not last. It is not a good idea to ignore comfort issues. We must protect the occupants of the home from hidden dangers, such as carbon monoxide, or water damage. When improving the energy efficiency of a home, it is very easy to improve the durability of the improvement with choosing the right material, and including the protective installation, for example flashing or a drainage plane around insulation.

I look forward to following the #DER conversation in more than 140 char bites.


Deep Energy Retrofits – A Twitter Conversation

My first Twitter Follower was SLS Construction.  He posted on his blog tonight about a Twitter Convo that I was participating in.

You can read Sean’s Blog Post here.  He does a great job for homeowners in general and for Energy Efficiency.

I jumped into a conversation between my friend John Poole of Derby, Connecticut and Peter Troast of Energy Circle.

John lives in a Derby that is very old.  In Connecticut they have houses that are 200 – 300 years old.  I live in Derby that is not so old. In Kansas and we do not have houses that old. John has a blog about preserving those old houses.  You can read John’s Blog here.  He has a neat Point of View and some very good experience.

Peter is CEO of Energy Circle. They work at explaining problems in building science, and providing real, actionable insights for homeowners to increase the energy efficiency of their homes. Energy Circle also provides energy efficient devices and products for consumers and marketing services to Energy Raters and Auditors.

Others that were mentioned in this convo were Chris Laumer-Giddens and Energy Vanguard.  Chris is an Architect and Energy Guy, Energy Vanguard, a twitter handle for Allison Bailes, is a physicist, energy guru and a juggler of some fame.  They hang out in Atlanta and other places, where Ya’ll is common.  You can find them at Energy Vanguard.

Here is a shot of part of the convo, just before I jumped in.








Somewhat later, John (from Derby, CT) posted a link to the Wiki definition of a Deep Energy Retrofit.

Wiki uses a 30% reduction in energy use as a line to define deep as in Deep Energy Retrofit.  I can accept a 30 % reduction for deep.

That level of reduction eliminates, in my climate zone (4), moving from an old 60 AFUE furnace to a 95 AFUE furnace, or a new AC unit, or spending a couple thousand dollars on windows, none of which will reduce an annual energy bill by 30%.  At this level, it would require air sealing work to reduce infiltration, insulation and then take a look at the equipment.

Any discussion of Energy Efficient Improvements, for me, also must involve some type of significant savings to cover the cost, and probably some work that will significantly improve the comfort, quality and durability of the home and the lives of the people living there.

Without going into too much detail in this post, that means most of the cost should be returned in energy savings in a reasonable time frame or work is done for the sake of doing stuff right.  Stuff is safety related, like fire safety, electrical safety or indoor air quality.

When the Twitter Convo seemed to hit the limits of the 140 char blog, Sean suggested that we draft our friend Leah Thayer to help out some how with the issues.  Leah runs the Daily 5 Remodel site and is a connector of people and ideas.  Sean threw out some ideas for a Blog Off type of pushing the 140 limit or perhaps some type of round table to do the same.

This post was to throw out two points on Sean’s wonderful idea and to keep the ball rolling

First the definition of DER – use the Wiki at 30%.  Second, the pushing of the 140 limit should be documented for ourselves and others.  I am open to the options, and look forward to continuing the extended convo.

Speaking of others, at some point AFF got involved with a comment about leakiness.  We all know and appreciate Alexandra’s and Kymberly’s efforts to keep us fit as a fiddle. AFF with her twin KFF are fitness and exercise (please excuse my use of the ‘E’ word?) gurus.