Tag Archives: systems

How do I start…

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… with energy improvements on my home?

This is probably the question I get most often.

Whether you are thinking about smaller improvements or bigger ones, like our deep energy retrofit, here are some guidelines on how to go about it.

The big picture

It is not just about energy improvements, but it is also about where you get the biggest bang for your buck. So let’s take a look at the big picture. 

For more data go to: https://www.eia.gov/consumption/

The 2015 chart above from the U.S. Energy Information Administration shows that up to 54% of energy for a single family home can go towards space conditioning (i.e. space heating and cooling). Only 5% of energy goes towards lighting.

If you decide to make your lighting more efficient, i.e. go with all Energy Star LED lighting, I applaud you. However, the total resulting energy savings may be around 1-2%. That’s something you may barely notice on your electrical bill.

If instead you would focus on improvements to your building envelope, i.e. your basement floor, foundation walls, crawlspace, exterior walls, wall penetrations, windows, exterior doors, attic, and roof, you could make a major dent in the 54% of energy that goes towards your space conditioning. This is where you can get a big bang for your buck. And not only that, you likely end up with a home that is a whole lot less drafty and a whole lot more comfortable and healthy to live in.

The bottom line is, don’t focus on the low hanging fruit. Look at the big picture and focus on the energy hogs, such as space conditioning.

Verify and quantify

You decided to not just chip away at your energy use but instead to make a dent, maybe even a really big dent.

Based on the data above, you know that you likely need to focus on your building envelope in order to reduce your space conditioning loads. But how good or bad is your building envelope, and what is the actual space conditioning load for your home?

It’s time to find out. Commission a home energy audit. A professional energy auditor will visit and inspect your home, analyze your utility bills, and may run several tests such as a duct, furnace, and blower door test. 

For more information on home energy audits go to: https://www.energy.gov/energysaver/home-energy-audits/professional-home-energy-audits

The energy audit report will point you to the areas where energy improvements can be most effective. The most significant recommendations will probably point you to building envelope improvements, such as insulating, air sealing, door or window replacement, etc.

With this data and recommendations in hand, you can begin to strategize.

Weatherization

You have a choice. Even basic insulation along with good air sealing (also called home weatherization) can save you an “average of 15% on heating and cooling costs (or an average of 11% on total energy costs)” according to Energy Star information. 

For more information go to: https://www.energy.gov/energysaver/weatherize/air-sealing-your-home

Depending on how handy you are, weatherization can become a DIY project or you can hire a weatherization specialist that does the air sealing and insulating for you. If you hire someone, make sure that you contractually set performance goals based on the home energy audit. This means how much more air tight the house should be after the improvements and what cold spots should be eliminated with insulation. And at the end, go and verify. In other words, have your energy auditor come back to test that the performance goals are met.

Energy model

You want to aim higher and save more? Good for you!

In this case I recommend commissioning an energy model, which your home energy auditor could provide. And if not, he or she can probably recommend someone. We commissioned an energy model in the planning phase of our project, which guided us through the decision making process.

An energy model takes a wide variety of building variables into account (type of windows, type of insulation, building exposure, air tightness, etc.) and predicts the energy load of your home. By adjusting the variables (i.e. thickness of insulation, type of windows, level of airtightness, etc.) you can see how the energy load of your home increases or decreases.

Say you want to decrease the energy load of your home by 50% or more, which puts you into the realm of deep energy retrofits. The energy model will help you to determine how to get there. It tells you what level of air tightness you need to achieve. It tells you what levels of insulation values you need, and where. It tells you what performance targets your windows and exterior doors should meet. And so on.

Decreasing your energy by 50% or more will involve major remodeling as you probably have to work on all exterior walls and the roof from the inside, the outside, or both.

Sounds daunting? Well, it can be. But there are silver linings here too.

Major remodeling allows you to get to all those quick fixes and deferred maintenance items that have been causing problems and eating money for years. And of course, you are left with major energy savings.

Take our deep energy retrofit. A preliminary analysis in 2016 showed a 80% reduction in our heating needs, and 57% reduction in our electrical use in 2012.

Be picky with your contractors

You will need help from various building trades with a deep energy retrofit. I highly recommend relying on contractors that specialize in energy improvements, or that are at least familiar with the topic. Working on energy improvements, such as in a deep energy retrofit, takes a very different mind set compared to regular construction, as the installation and construction processes often vary from the old norm. A recipe for disaster is a contractor that is set in the old ways, because that is how he/she has always done it.

Don’t tiptoe

Aiming high, such as with a deep energy retrofit, may seem expensive and overwhelming. You may think you should start in small increments instead.

Please think again.

Going about your improvements incrementally, each step in the process seems less overwhelming and less expensive. I’ll give you that. However you keep tiptoeing around big ticket items and associated savings (such as the above mentioned space conditioning). And you will likely end up undoing some of your own work along the process.

In the end, you may have spent cumulatively more on incremental improvements than on a deep energy retrofit with far less energy savings than you would have had if you didn’t tiptoe..

Learn how to operate your home

Owning a home, energy efficient or not, requires you to know how to operate it.

It is similar to owning a car: If you want to drive, you need to know how to start your car, how to steer it, how to accelerate and brake. You need to know what kind of gas you need, how to put gas in the tank, check tire pressure, check oil levels, etc.

The same is true for a home, in particular if you like to maximize your energy savings. You need to know when to change or clean which filters and when to schedule service appointments for what equipment. You will have to program and monitor your thermostat and other monitoring equipment. You should become familiar with the basics of indoor air quality (IAQ) and learn the basics about moisture management.

Owning a home is not a hands-off operation! There is no chauffeur. You need to drive if you intend to maximize your energy savings, assure the durability of your home and systems, and maintain a healthy and affordable living space.

Related posts:

Plumbing installation – hot water routing

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I mentioned the tree analogy that guides the plumbing layout in a previous post. Conventional wisdom is to have a trunk line with branches to each fixture.

In our case, conventional wisdom would have dictated three hot water branches serving the three hot fixtures – kitchen sink, bathroom lavatory and shower.

In order to minimize water and energy waste while cutting down on the hot water delivery time, we decided to rely on an on-demand hot water pump. The on-demand pump, once activated, will take a few seconds to prime the hot water trunk and branch line.

But this throws a wrench (pun intended) into the typical trunk and branch layout. We don’t need to reinvent the wheel, but have to fall back on recent developments in the hot water routing business.

To get the most out of the on-demand system, all three hot water fixtures should line up in series on one branch with the pump placed at the end, just prior to the last fixture, which in our case is the shower. The branch in turn supplies hot water to each fixture through short twigs.

We need to be mindful of the branch routing to keep the twigs as short as possible. The shorter they are, the more it cuts down on the hot water delivery time.

Data published by my friend and hot water guru Gary Klein, which I had listed in a previous post, makes for some simple math with interesting results.

  • The hot water twig to the kitchen faucet is about 36 inches long, delivering hot water from the primed branch in less than 1 cup (0.64 cup, to be precise). The corresponding hot water delivery time is less than 2 seconds at a fixture flow rate of 1.5 gallons per minute.
  • The hot water twig to the bathroom lavatory is about 40 inches long, delivering hot water from the primed branch in less than 1 cup (0.71 cup, to be precise). The corresponding hot water delivery time is less than 5 seconds at a fixture flow rate of 0.5 gallons per minute.
  • The twig to the shower head also is about 40 inches long delivering hot water from the primed branch in less than 1 cups (0.71 cup, to be precise). The corresponding hot water delivery time here is less than 2 seconds at a fixture flow rate of 1.5 gallons per minute.

I think it is fair to say that this qualifies as almost instant hot water delivery, once the on demand pump has primed the trunk and branches.

The priming would be initiated through the push of a button, typically first thing in the morning on the way to the bathroom, or in the early evening after the first person is back home from work. Anyone else using hot water after the priming and first use literally has instant hot water. That instant hot water lasts for two hours or more, thanks to the pipe insulation we used on our plumbing system.

This is not your typical approach to plumbing installation. It requires getting used to and focus on the part of the plumber to avoid falling back into the conventional trunk and branch system, which does little for water and energy conservation.

Service desert

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Do you have plans for some sustainable renovation or remodeling? If yes, it is very likely that you have given some thought to the project schedule. It is equally likely that you’ll need to commission the help of some experts, such as a mechanical engineer and an installer for the mechanical systems.

This is where it can get tricky, as we found out. Why? Because we sit in the metropolis Chicago, which is proud of its “green” accomplishments and incentives, and I expected it would teem with engineers and mechanical contractors eager to design and install cutting-edge, high efficiency building systems.

But Chicago turns out to be a service desert when it comes to affordable, knowledgeable and skilled green building expertise, particularly on the mechanical side of things and even more so for residential rehabs.

Let’s start at the beginning. We organized a design workshop late last summer and were on the move to finish the design for the green building rehab. Except that the process came to a screeching halt for about three months. I was unable to find a mechanical engineer – and I already had been looking for about two months prior to the workshop!

A mechanical engineer was absolutely critical to the process to assure that the insulation of the building envelope goes hand in hand with the type and size of the heating and ventilation system. My nightmare scenario was to end up with an oversized (and costly) heating system or an undersized insulation assembly.

Most capable and green-minded mechanical engineers I know through my professional network do not work at the residential scale. The few I knew or found that take on residential projects were booked to the gills and unable to help.

I finally stepped outside the Chicago market and contacted IBC Engineering near Milwaukee, Wisconsin. I had worked with IBC before and respected their expertise.  I was fortunate enough that they agreed to work with us.

This allowed us to restart the design process in November, three months after the workshop.

This was the first significant delay and only the first problem solved. The next one was already knocking at the door, namely finding a local, green, technology-savvy mechanical contractor. We knew that we need the innovative and out-of-the-box thinking kind.

Don’t get me wrong – they are out there – in rural Wisconsin, Michigan, Indiana or the far exurbs of Chicago, but not in Chicago proper as far as I can tell and I have done a lot of searching and asking around. And I am not the only one looking. I know of a couple of green-minded general contractors that are on the search for mechanical expertise in the Chicago dry lands.

How can it be that a population center such as Chicago is critically underserved, considering that the city has pushed green building technologies for quite a while? I expected a well developed if not saturated market but was mistaken.

If you are a future remodeler and interested in green building systems, be prepared to go on a search for the right expertise, because you won’t find it waiting on the street corner.
Here are some resources I tapped into during my search:

Do you know of any other good resources? Let us know and we will post them!

Design workshop

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Saturday 08/22/2009 – the scheduling and preparations are complete and the long anticipated design workshop is finally becoming reality. I have the energy model and an agenda – and most importantly – I have gathered a green team.

We started the day in the house with a quick inventory of the gutted basement and first floor. Because the house offered no comfortable or clean enough room in which to conduct the workshop, I had organized a meeting room one block north at Saint Agatha Catholic Academy.

workshop

Corbett Lundsford from the Green Team Group started the workshop session with a summary of the energy model results, providing us the foundation for the following discussions, which we had organized into the broad subject areas insulation, heating system, ventilation, and floor plan layout.

Insulation

The two key principles are super-insulated (high R-value) and airtight (elimination of leaks and drafts). Simple enough, isn’t it? To my surprise, this issue got us deep into rocket science. I will dedicate a post or two just to this subject – so stay tuned!

My research has pointed me to open cell and closed cell spray foam insulation. We discussed alternative materials, environmental impact, the objective of an airtight building envelope, R-value and point of diminishing returns, as well as moisture management in the masonry building shell.

The consensus that emerged was that spray foam insulation may not be the most economic option (ranging from $0.40 to $1.25 per board foot), but would allow us to effectively meet our insulation and air tightness goals in the building shell. Cellulose insulation, with a high recycled content, was suggested as an alternative for the basement and first floor ceiling, providing the needed insulation and sound attenuation.

Because we plan to install a new concrete floor in the basement, we discussed insulation under the new floor slab. With no insulation, the floor slab would provide a nice cooling mass during summer. It would, however, make heating rather inefficient. The final recommendation was to integrate insulation under the concrete slab. It would provide the right conditions for a radiant floor heating system, which leads us to the next topic.

Heating systems

Our preferred energy source for heating and domestic hot water is a solar hot water (SHW) system. The preferred heating method is radiant hot water, such as cast iron baseboard heaters. The green team was quick to educate us about the water temperature demand of hot water radiators (typically ranging from 150 to 180°F) and the capacity of a SHW system (typically ranging from 100 to 120°F). We have a 30 to 80°F temperature difference problem to solve!

Not only that, but the green team recommended a backup option to the SHW for those overcast and cold stretches. I would love to install a biomass furnace. The problem is that the best, cleanest and most efficient models are all European. The green team suggested a high efficiency condensing gas furnace instead. I could always switch to a biomass furnace once a clean and high efficiency model becomes available on the U.S. market.

With a temperature problem to solve and a need for a backup furnace, geothermal entered the discussion as an alternative to SHW. It could provide the energy needed for heating and domestic hot water. That said, I was concerned about the electricity demand by the pumps and condensers of a geothermal system, making our zero energy goal more challenging. Geothermal and SHW is something that will require more research and additional expertise.

Ventilation

Ever heard of sick building syndrome? That’s when a building does not get sufficiently ventilated, the air becomes stale and unpleasant and pollutants and toxicants start to accumulate. With our plans for a super-insulated and air tight building envelope, indoor air quality (IAQ) and proper ventilation becomes very important.

I was hoping for passive ventilation option to avoid ventilation duct work in the building. It would be difficult to integrate into the interior architecture without having it look ridiculous. I pressed the green team hard on passive ventilation, but had to concede that some duct work will be needed if we would like to use a heat recovery or energy recovery ventilator (ERV or HRV).

Basically, ERV and HRV are air-to-air heat exchangers, taking the energy from the exhaust air and transferring it to the unconditioned supply air. I now get the fresh air I need for ventilation at minimized energy loss. The tradeoff is that I need to have the supply and exhaust points at opposite ends of each floor. The green team’s recommendation was to consider lowering the ceiling by 6 inches (from 10 feet down to 9 ½ feet) and using the flat, rectangular ducts. Although cylindrical ducts would create less drag on the air flow, we’re making the esthetic choice to trade some flow for the ability to fit the duct work into the ceiling.

Floor plan layout

My idea was that after we had brainstormed and decided on heating and ventilation, we could look at the floor plan to determine what utilities should go where. Well, I had to table this discussion. The problem was that our MEP (Mechanical-Electrical-Plumbing) contact was a no show for the workshop. We had no one who had the engineering expertise to confirm the feasibility of our ideas or where to place and how to route utilities. Instead my research list grew and was to keep me busy for the next few weeks.

A big thank you…

… to our workshop green team:

  • Howard Allen – Howard Allen Architects
  • John Edel – Chicago Sustainable Manufacturing Center
  • Ted Krasnesky – Pepper Construction
  • David Lemaire – Hammerhead Carpentry, Inc.
  • Corbett Lundsford – Dream Green Group LLC
  • Drew Schmidt – student at Waubonsee Community College
  • Mark Weitekamper – GreenWerks, Inc.
  • Ryan Wilson – Conservation Design Forum, Inc.

Stuck in workshop preparations

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Coming from the design profession, I am a strong believer in the effectiveness of design workshops.

To kick off the design and engineering process, I had planned for a design workshop with architects, contractors and green building professionals (the so called green team). The intent of the workshop was to figure out how we would put everything back together and how to integrate the most appropriate and efficient sustainable strategies, systems and materials. The cumulative expertise and creativity of the workshop participants was to help us to organize our ideas, make sure that various wish list items are compatible, and make sure we accomplish our project principles.

A rehab is not a cheap undertaking, nor is a sustainable rehab. If we spend all this money, I would like to make sure that we get things right the first time round and that we can count on a reasonable payback and/or effective environmental footprint reduction. The workshop was an investment that will help us in this regard.

I developed a list of items to discuss and resolve in the workshop:

  1. Cathy and I very much liked the layout of the building. We now have floor plans of the existing conditions that include some of the original building features we discovered during the deconstruction process (see also 06/13/2009, 06/15/2009, 06/17/2009 posts). We would like to restore some of those original items and, in some instances, change their function – for instance turning the former pantry into a half bath room. I would like to review the floor plan with the green team to see what other ideas may emerge.
  2. Insulation is a very big, and as it turns out, complicated topic. It has a significant impact on many of the other systems we will need to operate the building. What kind of R-value do I really need? What kind of insulation would suit our project best? What kind of windows would go hand in hand with the insulation?
  3. I needed some input on space heating and domestic hot water. We favor a solar hot water system. But what would be the peak load the system has to meet – after we insulated the building? What kind of heat distribution system would work with solar hot water? We would like a biomass furnace as a backup for cold and cloudy days, but is this realistic?
  4. We plan to create an airtight building envelope (stop the building from leaking air in our out). That will, by definition, require a good ventilation system to keep the indoor air healthy. Can we rely on passive ventilation or do we need an active system (fans and ducts)? Does a heat or energy recovery unit make sense? How do we size the ventilation system and how much energy would it need to operate?
  5. The findings from the insulation, heating and ventilation discussion would bring us back to the floor plans and layout. Where should we place the various utilities and how much space would they take up? How could we route things (like ducts or pipes) in effective ways? Would our ideas require changes to the floor plan after all?

I put these items into a draft workshop agenda and ran them by my friends John Edel and  Ted Krasnesky (Pepper Construction). Both pointed out that I was missing baseline data on basic energy needs. That data would be the foundation for the workshop discussions (i.e. how well would the insulation work and how much heating do I really need?).

I needed an energy model. More importantly, I needed to find someone competent who can run that energy model for me – quickly. Never mind the bad economy. Energy consultants in the residential green building business seem to be extremely busy.

A visit to Chicago Green Drinks earlier this year got me out of this rut. I remembered a presentation by Corbett Lundsford (Green Team Group, LLC) about energy audits and modeling. Corbett was kind enough to squeeze me into his schedule. He ran a REM/Rate energy model for me based on the floor plans and building performance parameters we discussed. Thank you Corbett!