Rocket Stove

I finally got around to making a video about the rocket stove I made this summer.  It works great and was a fun project to work on.

On demand water heaters

When we were first planning our house I started researching on demand hot water heaters.  The idea sounded great.  You only heat water when you need it.  They do cost more and there seems to be a lot of people on the internet who complain about the problems they have with theirs. We ended up going for it and getting a Rinnai 94i.  We have had a couple of issues with it in the years that we have been using it.  The first was that the incoming screen filter got clogged with sand and debris and slowed the flow so that it won't fire.  I unscrewed the filter cleaned it and we were back in business.  The second issue we had was that a bunch of snow piled up on the exhaust vent and blocked it.  After sweeping it off with a broom it was working once again.  Other than that I try and run vinegar through the system once or twice a year to keep it from scaling up.

The most load we have ever put on it was two showers and the washing machine at the same time and there was no problems meeting the demand.  If you use low flow faucets and shower heads you could probably get away with a pretty small unit.  I would think that most people would call a big hot water draw two people showering at the same time.  If you had a 2 gpm head on each that would be 4 gpm if you had the water set all the way to the hot handle.  Since you can set the temperature that you want with a Rinnai you could set the temp to 110 F and then go with just the hot handle.  If you read their website the fine print say they assume a set temperature of 120 F that is mixed with cold down to 104F.

It looks like Rinnai now has an Ultra Series that are 96% efficient.  If given the choice I would choose a smaller Ultra model.  I wouldn't find it a big hassle to not start a load of laundry when two people were taking a shower but I think it could still manage that.

There is also an increase in lag time for the hot water to get to the faucet.  It is not bad but it is enough that it is not really worth it to try and wash your hands with warm water.  You will waste water waiting for it to heat up.  It also depends on how far you are from the heater as with any house.  If you are doing a sink of dishes then it is no problem to turn the hot water on and fill up the sink.

Noise is another issue to consider.  It is a little noisy.  Mine is located in the mechanical room that is attached to the outside of my house.  I can hear a low hum when the hot water turns on.  I would not mount this in an internal space like a pantry because it might be noticeably loud.  If you are considering getting one I would find one that is installed so you can hear the sound and see if that is a problem in your situation.

We use propane to cook with and heat water.  As a family of four with two small kids we use about 120 gallons of propane a year.  That is about 10 gallons a month at around $1.80 a gallon comes out to 18 dollars a month.  I really don't know what it would cost if these were both on electric.

Overall I have had a positive experience.

Garden updates

Now that gardening season is well under way I have posted a couple of videos describing some things in my garden that have been working well the past couple of years.

The first video is an update about my hoops that I created for my raised beds.

The second video talks about the drip irrigation system that I use for my raised beds.

Enjoy the summer!!

Rain Barrels - My design

I built my rain barrels a couple of years ago and have been testing them out before I posted a video of how they work.  So far they have worked exactly how I wanted them to work.  Watch the video below for design layout.

Heat Recovery Ventilator (HRV)

When you build a tight home in a cold climate it is recommended that you have some way for the house to allow fresh clean air into the house so that moisture and pollution do not build up in your house.  This could easily and cheaply be done by opening a window for a couple of minutes during the winter to let fresh air in.  The obvious problem is that the incoming air will be very cold and you will have to use more energy to heat that cold air.

This can be solved by a heat recovery ventilator. (HRV).  The basic idea is that the HRV unit has two fans in  it, one that pulls stale air out of your house and one that pushes fresh air into your house.  The process is improved by the use of a heat exchanger core.  As the warm air is sucked out of your house it goes through the core at the same time as the cold air from outside is travelling through the core.  The two streams never come in contact but they travel through little pathways that have a small amount of material between the two streams that allows heat from the warm air to warm the incoming cold air.  These systems claim up to 84% efficiency.  Meaning there is only a 16% loss in heat to the new air entering verses the exiting air.

Our HRV is made by Bryant.
http://www.bryant.com/products/airquality/heat.shtml

So on the surface it appears to be a great idea but there are a few things that you need to watch for or it is only a good idea.

The first is cost.  Our system cost around $5,000 dollars professionally installed.  This included the HRV unit as well as all the ducting.  Since we do not use a forced air system our ducting is only for the HRV.  Ours draws air out of the house from all three bathrooms and the kitchen.  It returns fresh air into all three bedrooms and the living room.  We use our HRV in place of bathroom fans.  When we take a shower we can push a button on the wall that runs the HRV for 15 minutes to help remove moisture out of the bathroom.  When you push the button and turn the system on it pulls air through all the bathrooms and not just the one where you pushed the button.  The "suction" of an HRV vent is not as strong as a good bathroom fan but it is quieter.

The second issue is the wall controller.  I mentioned the 15 minute bathroom wall timer, this is a great idea and we use it all the time.  You will have one main wall control unit that will give you more options.  Ours allows us to run the HRV on high speed or low speed, run automatically based on the humidity in the house or to recirculate air within the house without bringing in outside air.  All of which are nice features.  The main problem with our control unit is the humidity sensor.  It is so inaccurate as to be useless.  I would not recommend buying an HRV from bryant because their humidity sensors are junk.  I went through three different units looking for one that worked and none of them did.  Even the installers used their high tech humidity sensor to determine the humidity was 12 %  but the controller activated at 55%.  The sensor is made of a nylon coil that expands and contracts at different humidities.  I would only recommend digital sensors they are more accurate and more sensitive.  If the controller did work I could set it to 45% and if people were cooking and taking showers then the HRV would come on and stay on until it removed enough moisture from the house to get below 45%.  If our worked like that it would be great.

After further research I would look at going with a Venmar HRV.  I have never used one but their controllers look to be much better designed.
http://www.venmar.ca/air-exchanger.html

The third issue is easily solvable but you need to mount the control unit with a humidity sensor close to where most of your humidity will be.  In our house all the showers and laundry room are upstairs but the controller is downstairs.  Most days the upstairs feels much more humid than the downstairs but the sensor (if it worked) would not be responsive to the moisture upstairs.  So figure out where most of your moisture will be and wire the controller close to that location.

The fourth issue is the length of time that the unit must run to bring the humidity levels down.  It takes hours to see a change in the humidity levels in your house.  This also depends on the humidity of the incoming outside air.  The amount of electricity required to run this fan for hours just does not make sense verses opening a window.  When we take a shower in the winter we crack the window because it is a much faster way to get the humidity out of the house.  If the humidity gets too high in the house during winter and the wind is blowing I just open the windows for five minutes and the humidity drops rapidly.  I have an indoor digital humidity sensor so I can watch it drop by the minute.  Yes the incoming air is cold but after closing the windows the house warms right back up again due to the heat trapped in the objects of the house.

Overall the idea is good and the device works like it should.

Radiant floor heating

Well it has been awhile since I posted anything but I figured as winter is coming to a close I would leave a note about radiant floor heating.  Before we built our house we did a lot of research on radiant floors and most of it was very positive.  We were planning on having a stained concrete floor in the downstairs anyways so adding radiant heat to it sounded like a good idea.  We got a quote from a local company to install it and the price was ridiculous.  So we decided to install it ourselves with a kit from the Radiant Floor Company.  It was reasonable project for the two of us to do by ourselves even though it was cold and the tubing wasn't very flexible.

After we moved in and winter came we were excited to fire up the floor.  And sure enough the floor heated up and you could walk around in your socks and feel the warmth.

Then in the spring we installed a wood stove and now we rarely use the floor at all.  What happened?  Well many things.  Some were just a lack of research and understanding on our part and the other was a lack of experience in the use of radiant floors.

Here are the downsides.  First is the time lag to heat the floor.  It will take a while to heat the floor depending on the temperature in the tubing as well as the size of the zone.  Ours is around an hour.  Once the floor gets warm you then have to wait for the air to get warm.  Which takes even more time.  When it does get warm it does a good job of holding the temperature steady for hours.  

People argue that radiant floors are very efficient because you are not heating air that can escape your house, the heat is closer to the living zone of the room and blah, blah blah.  That all might be true but it is  crazy inefficient in the time lag.  For a normal family that gets up goes to work/school and then comes home in the evening a radiant floor does not do a good job of allowing you to set the temperature back while you are gone and at night and then heat quickly in the evening and for a short time in the morning while you are getting ready.  If you stay home all day radiant could work for you because you want a steady temperature all day.  Otherwise a forced air system on a programmable thermostat can provided cheaper and more comfortable use of heating by only providing heat when you need it.  If you are cold then bump it up a couple of degrees and you get that heat pretty quickly with forced air. 

The other issue, which is obvious but should be noted, is that it will never get really hot.  If you come in from working out in the cold you want to stand somewhere really warm to heat up you won't find that spot with a radiant floor unless you lay on the floor.  If you are using forced air or a wood stove that option exists and it is really nice.  

The next issue is also fairly obvious but was a surprise.  Yes heat rises but not radiant heat.  Since we have a two story house we were hoping some the the heat from downstairs would rise to the upstairs to help warm the upstairs.  That did not happen at all.  So we used the electric wall heaters upstairs to keep the bedrooms warm.

After one winter we realized with the help of a tax credit that a wood stove is a better all around choice for many reasons: cheaper, heats the upstairs, carbon neutral, works in a power outage, can cook on it, provides a place to warm up after coming in from the cold, The downside dealing with wood.  Since our SIP panel house is very tight we don't have to burn a huge amount of wood and the house holds its temperature very well overnight.  We use the heat recovery ventilator (HRV) to reduce indoor air pollution from the stove.  There is also the issue of the little kids touching a hot stove but a gate takes care of that while they are young.

Moral of the story is don't be so quick to jump on the radiant floor bandwagon.

Raised bed hoops and row covers

This summer I was determined to have a more successful garden than last summer.  I realized that one of my problems is that my garden is very exposed to the wind and weather.  During afternoon summer thunderstorms my plants get beat up pretty bad especially if it hails.  I decided to try and make some hoops and purchase some row cover fabric.  I ordered Agribon - 19, 83" x 50' from Johnny's Selected seeds .  From the little bit of research I did I decided to use 1/2" conduit to make the hoops.  It was surprisingly cheap at $2.00 for 10' of conduit.  PVC was about $1.50.  The problem was bending the conduit to the shape of my raised beds.  Johnny's also sells a tubing bender but it was a little bit expensive and what would I do with it after I was done?  I decided to try my hand at bending them myself. Here is the video I created to show how I did it.



So far the hoops and covers are working great.  We have had a number of storms come though which included some hail and the fabric has held up great.