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Convincing Home Owners to Upgrade Efficiency

 

Empty glasses and empty promises for vertical integration and a national energy industry. I spent the dog days of summer ’88 pumping gas at Petro Canada and handing out all manner of commemorative glasses – the price of gas today is about the same as it was back then.

As I write, the price of gas at the pump sits well under a dollar a litre which is about the same price it was when I worked a summer at Petro Canada slinging gas at the pump. The price of delivered natural gas is about 32 cents a cubic meter and with these low prices, the financial incentive to conserve is low on the list of priorities for many Canadians. What humbles me is the fact that I can hear myself repeating to homeowners throughout the early and mid 2000′s “Mark my word, the price of energy will go through the roof!”

Though electricity prices have steadily risen, my words have come to haunt me in that prices are still low, especially for natural gas, to the point where I should wash my mouth out with soap – but my, the House of Saud keeps us on our toes! So what’s the incentive for home owners to build a home that’s significantly better performing than building code minimums? More to the point, how does one convince a client to invest in efficiency? Baring the moral issue, it’s the right thing to do for durability, health, low maintenance and increased resilience to natural disasters, but how do we convince owners who are on the fence?

It’s a question Micheal Maines (from Maine!) tackles in a recent Guest Blog posted in Green Building Advisor titled Convincing Clients to Upgrade to Pretty Good (or Better). Because we deliver services to other businesses, we don’t often have to deal with the building owner and thankfully, eschew many of the hard questions we once had to answer on a daily basis when we delivered home energy audits for government rebate programs. Still, there are solid points to be made.

Jim Bahoosh of Jim Bahoosh, Builder —  suggests that “no frost on [better] windows” and that energy audits for those considering a full gut/reno should be mandatory. Chris Briley of Briburn Architects, and great podcast Green Architect’s Lounge suggest using “science” and to spend on ventilation. In the end all agreed, that making it beautiful was essential.

At BlueGreen Group, we couldn’t agree more and always emphasize hiring an experienced architect who can walk the razor’s edge pulling between doing what’s right and the ‘house porn’-like expectations of what we’re told we need. A good architect will provide a builder with details needed for high performance and should make the house beautiful for generations of easy and loving low-maintenance.

We also believe that science and detailed energy modeling informs the decision making process, keeps the ‘gut feeling’ in check and simplifies decision-making. This applies to both new construction and Deep Energy Retrofits of existing homes.  Let the data talk, but beware, as the old saying goes “Garbage in, garbage out” and the person doing the energy modeling needs to know how to process data with the software.

The other thing we’ve learned is that doing a pre-drywall air tightness test is crucial. In 2012, the Ontario Building Code changed and now building inspectors are compelled to “inspect” the air barrier and sign-off. This sounds rigorous, but is really toothless. Inspectors should be TESTING the air barrier. That’s where we come in with our equipment and help builders get more value from their sub-trades especially the spray foamers who often miss spots, unintentionally skimp on thickness or in rare cases go off ratio.

So until building inspectors test building shells with a blower door, take quality and performance into your own hands and TEST the building BEFORE the drywall goes on. This simple 3rd party test can save you lots of grief in the long run and ensure the home owner is left with lasting beauty no matter which way energy prices go. To those of you who already know the value of testing, not just ‘inspecting’, we raise a full glass to your continued health!

 

 

 

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New LED Lights on the Scene!

In 1999, I went through the back service doors of Wolf Electric on King St. just West of Bathurst and fumbled my way along the poorly lit, uneven floors to drop $37+tax for one compact fluorescent light (CFL) bulb made by Philips. It was the start of energy efficient lighting and quite possibly the apogee of CFLs given that store shelves today are littered with crappy CFL lights that aren’t dimmable, are filled with hazardous mercury and the ballast produces so much waste heat that the white plastic base quickly gets cooked to a yellow crisp as they sputter to an early death. So much for energy conservation.

But hang on… Is it just us, or did 2015 just usher in a new era of LED lighting? It seems LED’s have jumped out of the dark ages by offering dimmable features, lighting systems that tie into home automation to change hue from your smart phone, produce a truly beautiful light that doesn’t oscillate and one can read a book ( durable, sharable, battery-less device made of bound paper having stories printed in ink ) and lets not forget the fact that these lights “could” be substantially more durable than CFLs without mercury.

As you well know, pot lights installed through the top ceiling’s air barrier have been a big pet peeve of ours, not because we don’t like the lights, but because they kill home performance. The great news is that a series of new LED lights have flooded the market recently which might be able to significantly reduce heat-loss through air leakage.

Surrey BC company Lotus LED Lights has been retailing some exciting low profile pot lights that could substantially reduce the fussiness of installing pot lights. It should be noted that good quality LEDs typically have aluminum heat sinks and for good reason; the heat needs to dissipate so take this next sentence with a grain of salt. These new lights could potentially eliminate the need entirely for the large housing box that punctuates the air barrier system and projects into the attic to disturb uniform, continuous insulation and leak conditioned air like a sieve. Sadly, many electricians don’t get air sealing but these new faux-pot lights might be able to help them because many models install directly into a regular octagonal junction box. That simple!

What’s really exciting is that there may be a retrofit opportunity to easily air seal 90% of air leakage that occurs through pot lights by simply installing a new type of LED. Coming from a guy who made a living by sending other guys into hot, itchy attics to air seal the backs of pot lights – this seems like a no-brainer retrofit solution:

LED 2

If the flange assembly of this LED light is air tight and if it can be installed tight against the drywall, or existing metal flange, this might be the easiest retrofit for pot lights in the world and a steal at $35-$45 apiece when compared to sending a guy up into the attic to retrofit a drywall box or plastic VB boot around the leaky IC rated pot light box.

LED 1

Dimmable and looks like it might form a better air seal at the ceiling flange than conventional light bulbs, plus it gets the ENERGY STAR logo!

I’m proud to say that the same Philips CFL light bulb I bought in 1999 has been on a motion sensor in my back yard – extremely exposed to the elements protecting us from marauding racoons – for the past 10 years and is still going strong. My money’s on Philips for their commitment to quality and durability in this next wave of LEDs.

 

 

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Commissioning ERVs

We were recently called to commission a fully ducted heat recovery ventilation system in a house. The commissioning process was based on CSA-F326, Residential Mechanical Systems to ensure the system didn’t change the pressure in the house and to adjust flows room by room according to the intended mechanical design. In this case the ERV in question was an Enthalpic or Energy Recovery Ventilator (ERV) and what we thought was going to be a straight forward job turned into a multiday, time gobbler that taught us a few lessons.

At risk of stating the obvious, mechanical ventilation systems will either pressurise a home or depressurise it if not commissioned:

The house in the middle is “just right” and had to be commissioned to confirm the ventilation system was “balanced” – that is the pressure inside the house is the same as outside. The house on the left with a “blow only” ventilation system is pressurising the house and possibly driving humidity into the building envelope – which can cause condensation leading to mould, whereas the house on the right with the “suck only” system is pulling in cold dry air from the outside when it’s on.

It should also be noted that NO ONE designs or installs HRV or ERV thinking it might need to be commissioned before occupancy. Typically these units are tucked high into a corner of the basement mechanical room with flex-duct contorted and crammed on all four stations. On flow accuracy, doing a transverse with a Pitot tube comes in 3rd, followed by the more convenient insert type linear type flow measuring station which would come in 2nd place and of course, the best is to install a four quadrant flow measuring station despite the labour involved to re & re.

Lab Setting for ERV

NRCan shows above what the Laboratory set up looks like. Replete with flow straighteners and nice straight lengths of duct before the taps – it won’t look like this in the field.

 

Real HRV - Not bad for Straight runs

Typical HRV with OK access to ducts.

 

Real HRV

Typical ERV installation with constrained access.

 

The four quadrants of the ERV for the correct terminology. Thanks AHRI.

So we proposed another method or measuring total air flows. In speaking with the top scientist at ACIN in the Netherlands about our method using the FlowFinder Mk II, it was suggested that the error of the method proposed below could be a bit higher than 3% which given the alternative sounded acceptable and well within CSA-F326 10.2.1′s suggested -+15%!

Exhaust Dec 23 2014

Stations 1 & 4 were the same shape. We taped the cardboard flange to the perimeter of the vent in order to get a reasonably good seal with our balometer. The back-draft dampers were not in the hood, but in the duct. Three sequential measurements were taken to account for potential errors due to wind.

So armed with flow measuring stations, Pitot tubes and our new balometer, we started measuring to find where our TVC might be on the variable speed control board. This would then allow us to adjust flows room by room, except that the flows in and out of the house were off. Way off. They were off at Stations 1 & 4, they were off at Stations 2 & 3.

There were no adjustable dampers for this ERV, so we changed jumpers on the mother board and started undoing duct-work to check that inline back-draft dampers were OK. Still, the flow rates were impossible. We were getting in some cases over a 100cfm more exhaust air (Station 4) than outdoor air (Station 1) and no HRAI ventilation course could have prepared us for what we went through.

In the end, common sense prevailed over a few weeks. Using a Watt meter, we diagnosed something the matter with the control board. The board was replaced and things were better but still not ideal. In the end technical literature suggested that it was common for ERVs with a media wheels to mix in extra ‘purge’ air to combat cross contamination which might explain our difficulties.

 

Are fan motors blowing air through the media filter or drawing the air through it?

 

Net result

Clearly numbers for a commercial system, but Venmar shows graphically the relationship between air flows.

 

By design, this meant that flow at station 1 wouldn’t  equal flow at station 4. The ratio between those two flows is called the Outdoor Air Correction Factor (OACF) which ideally should stay as close to 1.0 as possible. There’s another cross contamination measurement called the Exhaust Air Transfer Ratio (EATR) -  the ratio of the exhaust air transfer to the supply flow rate.

The ERV in question was tested in ‘general’ accordance with CAN/CSA-C439-00, Standard Methods of Test for Rating The Performance of Heat Recovery Ventilators. The OAFC wasn’t available, but the EATR was calculated at 0.09, which according to the manufacturer, translates to about 3% of exhaust air being transferred into the fresh air stream. In other words, if we wanted 100cfm of fresh air delivered, we’d have to bump it up to 103cfm.

This might work in the lab, but not in the field where we were getting differences of 100cfm possibly due to a large OACF, possibly due to the home’s unique, custom duct work and or the added resistance of a pre-heater. Although the ERV in question was tested to CAN/CSA-C439-00, it wasn’t listed as HVI Certified (AHRI if a commercial unit).

 

In the end, we went with our DG700 and measured the pressure across the building envelope to ensure the system was ‘balanced’ when the ERV was running at TSV. CSA F326 states that flows in and out must be within 10% of each other and typically the flows are measured at stations 2 & 3 if the duct work will allow.

The lessons learned included ensuring the mechanical designer selects an AHRI Certified model and that the heat exchanger core uses a membrane that prevents cross contamination. Measuring flows at stations 4 & 1 or 2 & 3 gave meaningless data because we didn’t know how much of it was due to cross contamination. We were better adjusting flows room by room, then simply ensuring the house pressure was neutral at TVC. Having witnessed the build at the bare duct stage, we knew duct leakage wasn’t an issue, though we could have tested for it. We’re certainly going to ask builders to start supplying a chunk of straight pipe and flow measuring stations at Stations 2 & 3 from now on.

Though it probably applies more to commercial systems, Venmar suggests “If OACF is ignored in the selection process, then the prescribed amount of fresh air will not be supplied to the space and poor indoor air quality may result—in addition to creating numerous potential issues with balancing and commissioning.” and we’d agree on the point about commissioning.

For a through treatment the calculations and explanation of jargon above, AHRI’s How ERVs Work section is brilliant. I’d also recommend downloading and reading NRC’s pdf for insights into the testing process: Evaluation of IAQ Impact of Balanced Residential Ventilation devices that incorporate HRV and ERV.

 

 

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Ventilation for a Cold Canadian Climate

In Ontario, sadly, the residential building code still allows for cheap and infective ‘exhaust only’ ventilation systems and as Joe Lstiburek says, these systems suck – literally and figuratively.

OBC 9.32.3.4 Principal Exhaust“VENTILATION FAN” This system only sucks"

The sign of a cheap home: The photo above shows the wall in a typical living/dining room with artwork, a thermostat, a light switch and “FAN SWITCH”. Though declining in popularity since 2012, the Ontario Building Code section 9.32.3.4 still allows suck only systems as long as they are labeled “VENTILATION FAN”. This switch controls a bath exhaust fan one floor above. Make sense?

As the number of quality homes increase in the marketplace and get more air tight, “Suck only” ventilation systems are not being installed as often, but being replaced with systems that “recover” heat or reject it depending on the season.

Home with exhaust only ventilation systems e.g. bath fans, range hoods – exhaust only ventilation is about as effective as the old “Shut the Front door!” technique.

When compared to “Exhaust only ventilation” systems, ERVs and HRVs save energy by recovering conditioned air temperature.

Once properly adjusted or commissioned, the best ventilation systems don’t affect the pressure inside the house and the debate turns to Heat Recovery Ventilators (HRV) versus Enthalpic Recovery Ventilators (ERV).

Both ERVs and HRVs recover heat (sensible heat recovery), but what separates ERVs from the more common HRV is the fact that only ERVs maintain humidity levels (latent recovery).  Retaining humidity levels indoors at the ideal range of 40-50% RH in cold climates is difficult if a ventilation system needs to run continuously and doesn’t have latent recovery like the ERV does.