First Blog since May 2015! 

Image showing steel with Fabreeka insulation pad at Elm Place Multifamily Passive House

Again a year has gone by. I'm obviously not very good at this whole keeping up on the blogging thing. Things have been going very well with my work.

Since last year May, when I last posted I have been involved in many project. Most of which have been built. 

The three big projects (four actually) are:

•  The finishing of the South Hero Passive House
• The client moved in last fall. They are very happy with the house and how it is performing. It will be interesting to see how it performs.
• The house is being monitored so we should be able to get some great data on 
• Energy use
• Temperatures throughout the house
• Moisture in the double stud walls

The South Hero Passive house. A 3600 sq ft house with a

heating load of 15kBtu/hr at -1 F!

• The Middlebury Passive House with Gregor Masefield
• This is a great project as well. The owner and architect wanted to build a moderate sized house with modern styling which would be reproducible in many locations.
• This house has been rebuilt in another location nearby, with a slightly bigger square footage

This building is constructed with the Arctic wall. A 2x4 structural wall with a layer of Zip sheathing as air barrier on the outside and then a 12" TJI on the outside which is filled with cellulose. 

Although it looks like an unvented roof, this flatish roof is actually vented.

• Elm Place Senior Living Facility
• This is a very exciting project and the first Multifamily project I have been fortunate enough to work on.
• This 30 unit, senior living building is currently being constructed in Milton, Vermont
• Crazy of crazy's this 25,000 square foot building will have a heating load of only 170 kBtu/hr at -15F!  I know single family houses that have a bigger heating load than that!
• Cathedral Square and Duncan Wisniewski Architects were enthusiastic supporters of making this project work as a Passive House since the start of design work. It is a pleasure to work with organizations and architects who have taken the Passive House standard and made it their own!
• This building is expected to be ready to be lived in by Spring of 2017! 

I have also been working on other projects. Doing consulting and giving presentations to groups about Passive House, but also about building energy and durability.

Eco Houses of Vermont is partnered with Caleb Contracting providing Energy Assessements for homeowners. Giving them a clear picture of how their homes are performing and acting. We give advice as well as perform weatherization and durability work. 

Durability work is making sure that the structure is not rotting, getting mold, or falling apart in other ways. Very often work on durability is directly associated with fixing things other builders did. Builders who don't understand building science and how to treat a building as a whole system.

We have performed more than 250 audits in the past three years. Helping homeowners of existing houses to live in a more comfortable, healthy, safe and energy efficient home.

I'll speak more about this in future blogs.

That is the update for now!

Super Insulation Do's and Dont's and learning as you go

The Super Insulation Building Revolution, started in the 1970's has gone through fits and starts, but one thing that is a constant throughout. It is a movement where building science reigns. As with any discipline where science is used as the basis but the practitioners are not scientists, the application produces good results and ok results and bad results. It is a learning process. Not just in what you build as a builder or architect, but in what tools you use to design and construct the building.

As a designer/consultant in the Super Insulated Building community in Vermont I have been working for years to understand how buildings work. I'm not a scientist. I'm not in the field designing experiments and correlating data and analyzing the results. I'm in an office working on designs, trying to design the energy use of a building so that it is as low as it can be within the constraints of site location, client desires and budget. In the process I am also trying to make sure that the homes I help design are durable. That they will perform not just thermally but that they will be healthy, safe and last for a very long time without material failure.

The tools available to help me discern the expected durability of a wall construction are varied. I am leaning on the shoulders of great building scientists who are in the field doing that work. John Straube, Joe Lstiburek, Peter Yost, Alex Wislon, just to name a few. These scientists and their peers are producing the information we need as designers, architects and builders to do our best.

Only by constantly studying their work, going to seminars given by them and generally keeping up with the developments in the field can we learn the Do's and Dont's that govern good building design.

Yet there is a rub there. My friend and colleague, Jim Bradley of Caleb Construction in Cambridge, Vermont has said to me on many occasions,"I go to the conferences and listen to the experts and it seems that every year their advice changes. The perfect wall is perfect that perfect changes."  Jim is absolutely right. Building science is changing all of the time. The themes stay the same. What we learn is updated as we continue to learn what is right. What works, what doesn't.  As we change the types of construction we are using, the intricacies of how these walls, floors and roofs operate, independently and in conjunction with one another changes.

"We are experimenting, building experiments with each new design." This loose quote is from a PH Builder Trainer at a recent builder training. It can be unsettling but it is the truth. The other truth is that all of the other builders in the country are also experimenting. We are all doing what we think is right. Some of us are focusing on houses as whole systems and we think that we are right. I happen to agree with this. I have been on energy audits and seen the rotting remains of walls and roofs that were built with what the builder considered to be proper building practices, yet the wall/roof failed.

In my opinion what we need to do is move forward with caution but still move forward. When we build a home and later find out that we might have done something questionable we need to stand up and say I think that might cause an issue in the future. Let's go and take a look at this to see if my concerns are justified.

Furthermore, we need to learn and keep in mind the abilities and the limitations of the models we are using. Any modeling software can only give you good advice/information if you know its abilities and limitations. We need to be properly trained in the use and inputs for these programs and also in how far the information we get from them can be applied to our designs.


Forward and upward for sure, but with eyes wide open.

Chris West

Next steps

You would think that it is easy to finish off a project like this. Yet when you are doing lots of the work yourself and you don't mind a bit of a mess it can drag on!

We are now having the drywall installed in the basement. Has to be done in two parts due to the fact that we are living in the house during the renovation and are using these spaces. One space needs to be made empty to allow for work, filling the other with stuff. The empty space gets sub floor, sheetrock, paint, floor, trim, installed cabinets/etc. and then move all of the stuff from the other room into the finished space to allow for the unfinished space to get finished.

This while doing all of the regular work of life.

I am working on an analysis of the energy use of the house this past winter. It was quite the winter. It looks like we spent around $800 to heat the house for the heating season. We would have spent more than $4000 to heat the house before the retrofit. I'll have hard numbers on what we used soon and projecting it to what it would have cost before the retrofit will be difficult.

This heating season so far had 8200 Heating Degrees Days. The usual Vermont winter is 7200 HDD. That is a 13.8% increase! It's not over yet either. Yesterday's nighttime low was 25 F. Last night it was in the upper 30's.

Fortunately the house doesn't really need heat if it is above 40F and it is sunny out. The solar heat gains are enough to heat the house to 70F+ and the super insulation will keep it warm through the night.

If it is not sunny then we do have to put the heat pump on.

I will be submitting the house to the Thousand House Challenge, but need to get a year's worth of data first (November to November).

Still not certain if we are going to go forward with one heat pump or if we might add one smaller one in one of the upstairs bedrooms to make sure we have enough heat.

A Heat Pump to Keep you Warm

A Heat Pump to Heat the House

So you take all this time and money and make your home super insulated. You make it so energy efficient that you can remove your oil boiler and your baseboard heating. What do you replace it with?

My answer is an Air-to-Air Heat Pump. What is that?  A heat pump uses the same technology as an air conditioner or a refrigerator. The basics are that you compress a gas (refrigerant R410a or similar) to a liquid which gives off heat. You also let this liquid evaporate to a gas which takes in heat (gives off cold). If you want to heat your house you capture the heat part of this circuit. If you want to cool your house you can capture the cold part of this circuit.

Think of your refrigerator. Inside it is cold (the expansion part of the process) the back of the refrigerator is hot (the compression part of the process). The heat pump uses the same process.

Heat pumps are also super efficient. They take 1 kilowatt of electricity and make 2.5 kilowatts of heat. How can it do that? It uses the relative heat of the air (up to -18F) to boil that refrigerant. That is free 'heat' from the outside air. That is how it gets more heat out of 1 kW than 100%. These units are 250% efficient!

You see in the picture above the outside part of the system. This type of system is called a mini-split. It is a split because the condenser and evaporator are in separate places. Here is the inside unit.

The wall around it isn't finished just yet but it will be soon. 

With the system as I have designed it, based on super insulated houses in Vermont, the warm air blows into just one room. This moves through the house using natural air flow. But natural air flow isn't enough to do a really good job of distributing the heat. We are also using a Heat Recovery Ventilation system (HRV). This HRV is a marvel of modern building science.

Here is the HRV. It isn't ready yet. I'm still 

installing it. When finished it will save on

heating costs.

It draws warm but stale air out of the kitchen, bathroom and mudroom and transfers the heat from this air into the cold but fresh air from outside. It does this at an efficiency of 85%! This means when you put 0F outside air into the HRV and you have 70F inside air the fresh air comes into the house at 59.5F! 

If you are getting fresh air in your house at 59.5F then your heating system needs to warm it up just 10F instead of the 70F you would need to warm it up if it was coming in at 0F!

Thus a smaller heating system can heat your house.


Short Cycling

One issue that some point-source heat pumps in super energy efficient homes have been having is short cycling. This is when the heat pump turns on and off many times each hours. It is bad for a heat pump to do this. It decreases the efficiencies of the heat pump and causes wear and tear on the compressor, shortening its life.

Peter Schneider, senior energy consultant at Efficiency Vermont, found that the heat pumps in the homes he was working on were short cycling. He found this out because he was/is monitoring these houses. Each system has monitors on them showing when they are on, hoe much energy they are using and their efficiencies. 

Data monitoring is a great way to see how a house is performing. Peter was able to determine that the heat pump was short cycling by looking at the monitoring data on the heat pump. What he discovered was that the inside unit of the heat pump has a temperature sensor, a thermostat just like the one on the wall in your living room. If the room it is in gets to the set temperature it turns off. Once the heat leaves the room (migrating to other parts of the house) it turns back on.

The solution for this was to move the thermostat from inside the room the unit is in to a distant room. The heat pump then stays on until that room is at the set temperature. Since it takes longer for the heat to reach that room the heat pump doesn't turn off and the short cycling stops, protecting the compressor and keeping the efficiency of the heat pump high.


When can I use a heat pump?

You can put Air-To-Air heat pumps into any house. Just make sure that you have a good idea of how much heating your home needs and to have enough heating capacity (large enough heat pump or multiple heat pumps).

Do I need a well for a heat pump?

It depends on which type of heat pump you choose. 

There are two main types of heat pumps. Most people think only of the ground sourced heat pump. These are very efficient units but are quite costly to install. They use the relative heat inside ground water. Therefore you need to drill wells (or use your water well) and a distribution system in your house like radiant floor heating or low temperature radiators.

The second type of heat pump is the air-to-air heat pump. This doesn't require wells or a distribution system (radiant floor or radiators). It just blows warm air into the house. 

Air to air heat pumps are by far the cheapest option for new homes. If they are super insulated homes you can use a heat pump with a very low output. 

Some Passive Houses have an air-to-air heat pump with only 9,000 Btu/hour output. To put that into perspective a 2000 sq ft home built to Vermont Residential Energy Code needs a 120,000 Btu/hour boiler! That is a 92.5% reduction in the power of the heating unit!

Deep Energy Retrofit Blog moving to Blogger for ease of use

I have been blogging about my passion for super energy efficient homes for the past year and a half or so. Up to now all of my blogs have been self built on my website www.ecohousesofvt.com. I have put lots of time into formatting and uploading, etc. I would much rather use this time to actually work on projects and write/broadcast about them.

For those of you who are just starting to follow this blog I will spend a bit of time on the background story. 

My name is Chris West. I am pushing 50 and have been fascinated by the energy we use to heat and cool our homes for years. In 2010, I returned back to the US after spending 10 years living in the Netherlands (Holland) where I got a Bachelor's in Science in Mechanical Engineering. While in the Netherlands I spent time working towards a better understanding of how buildings work and how we use energy in our buildings. 

Upon returning I decided to get certified as a Passive House Consultant. Passive House is the most energy efficient building standard in the world. With the thoughtful application of modern building science we now have at our disposal the tools to make homes that use almost no energy to heat or cool. A big step in the right direction.

When I moved to Northwestern Vermont in 2010 I bought a rather simple house. It is a 1976 raised ranch pictured here with someone else's dog. This is what it looked like when I bought it. It 'ticked all the right boxes' as they say in England. Not to far from an airport or hospital yet secluded, in the woods. Not a beautiful house but more than enough for me, my wife and two kids. 

I was in for a big surprise when we had our first Winter. Not because we were taken aback by the cold, we know Vermont and were expecting it to be cold and even like the cold. No, it was the amazing amounts of fuel we needed to burn to keep the house warm, and this was before heating oil hit $3.95 a gallon.

There are many design problems with my house which detract from the amazing view out of our front window. The biggest was that one quarter of the space in the house was taken up by a 'tuck under' garage. It was a 'heated garage' meaning that there was a heating circuit that sent hot water through radiators in the garage but it was still almost as cold as the outside temperatures. This garage was below my bedrooms! The floor of the bedrooms was freezing most of the Winter (which in Vermont starts in early November and ends in late March). The two nine foot wide and seven foot tall garage doors were a big part of the problem.

The task at hand

What to do about this house that hemorrhages heat in the heating season? The heat in the Summer was bearable for the most part, but we needed to do something about that heat loss!

The plan is to get rid of the garage doors, take the garage space and make it conditioned floor space. Then once that is done to super-insulate the house.  How to do this is part of the story of this blog. The rest of the blogs will be about my experiences on other high performance projects and energy audits of existing homes.

To bring yourself up to speed start off at my online blog at www.ecohousesofvt.com. After you are done with the last blog you can come back here for the continuation.

Thanks.

Chris!