PTCS Program Newsletter: October 2020
In this issue:
PTCS Remote QA Inspections and Contractor SPIF Incentive
Testing Heat Pumps in Cold Weather
Testing Ducts in Cold Weather
Successful Heat Pump Sizing - What About Cooling?
PTCS Training Videos
BPA.gov Energy Efficiency Website Refresh
Ask the Contact Center
PTCS Remote Quality Assurance Inspections and Contractor SPIF Incentive
To increase participation in the PTCS program’s remote quality assurance, or QA, pilot for air source heat pumps, your local utility and BPA are offering a $250 per project contractor sales performance incentive fund, or SPIF to PTCS-certified contractors. Funds are limited and provided on a first-come, first-served basis.

The pilot will help ensure the heat pump is commissioned while your technician is onsite, avoid return visits, reduce administrative time and limit interruptions for your customers. We expect remote QA inspections for air source heat pumps will be standard following this pilot, and your input will be valuable in streamlining the process.

To participate or inquire about this offer, please contact us at ResHVAC@bpa.gov or 1-800-941-3867.
Testing Heat Pumps in Cold Weather

Here's a refresher of the specifications and some pointers for testing heat pumps in cold weather.

If the outdoor temperature is 65°F or less, test in heating mode after operating the heat pump for a recommended 15 minutes. This is to allow the system to reach a steady state condition (where the temperatures and pressures have settled and are representative of the system operating performance).

Temperature change across the air handler indoor coil must be at or above the minimum temperature split shown in the R-410A Temperature Split Table. The table requires a few inputs: CFM per ton and outdoor temperature are used to obtain the minimum temperature split allowed. Your measured temperature split should be above the one located on the chart.

Variable speed heat pumps often run at part load and can make measuring airflow and the refrigerant test difficult to interpret. Put the system in test mode at 100% airflow and 100% compressor speed (check out the Thermostat Support Sheets for assistance), allow the system to reach steady state then measure the air flow and temperature split to compare to the temperature split table. VSHP’s often will produce a higher temperature split than the minimum temperature split chart by 5-10 degrees. This is not an issue if the auxiliary strip heat is not activated.

If the outdoor temperature is below 35 degrees, the strip heat might turn on. If you find a larger than expected temperature split, make sure the strip heat is not engaged.

Remember, other refrigerant measuring methods approved and documented by the manufacturer are also acceptable. If you use another refrigerant measuring method in your commissioning, please add a note in the note field of the registry and let us know so we can make sure your registry input is accepted. Contact us at ResHVAC@bpa.gov 
or 1-800-941-3867 for review and approval of the entry.
Testing Ducts in Cold Weather

Testing ducts in the winter may provide unique challenges compared to testing in milder weather. For example:

Thoroughly check for all combustion appliances in the home to ensure a safe testing environment. Running a duct test can be very dangerous if a fireplace or wood stove is in use or was recently used prior to arriving at the job site. An extinguished fire in a wood stove or fireplace may allow left-behind ashes to be pulled into the home. Typically the blower door does not pull loose ashes into the home, however still monitor during the test. In particular check for fireplace ashes when the blower door is running at low speed.

Homeowners may think that cold air drawn into the home will impact their heating bill or comfort, but one can assure them that the impact is minimal. Here are a few tips to follow during testing that will reduce homeowner concerns:

  • Avoid testing adjacent to the main body of the home. Use another door located away from the homeowner.
  • Fully set up equipment and be ready to test prior to running the blower door fan.
  • Use the blower door fan cover when you are not running a test.

Prior to starting the duct sealing, don't forget to ask homeowners for clues to the condition of their ducting. Ask about strange smells when their heating system is running, cold or hot rooms, dirty filters, or other issues.
Successful Heat Pump Sizing - What About Cooling?

Even as we tend to have larger heating loads than cooling loads, we still need to consider sizing for both. PTCS requires sizing heat pumps to achieve a heating balance point of 30oF or less. If the heat pump sizing calculations suggest a larger cooling load than heating load, then achieving a heating balance point of 30oF or less will easily be achieved and may result in a slightly oversized heat pump for heating. However, in most cases, the calculated heating load will be larger than the calculated cooling load, and the heat pump will be appropriately sized for both. Since we are in a dry summer climate, generally there should be minimal concern about oversizing for cooling when sizing a heat pump for heating.
 
When sizing for cooling loads, the critical inputs are window orientation, solar heat gain coefficient, window shading, duct location, and duct condition.
 
Window Orientation – East and west-facing windows have the biggest impacts due to the low angle of the sun in the morning and evening during the cooling months.
 
Window Solar Heat Gain Coefficient (SHGC) – SHGC is the fraction of solar radiation admitted through a window -- either transmitted directly and/or absorbed, and subsequently released as heat inside a home compared to a single pane of glass. In the northwest, the SHGC usually aligns with the U-value of a window. Hence a window with a U-value of 0.4 would have SHGC of roughly 0.4.
 
Window Shading – Shading happens in many forms, including from trees, neighbor’s homes, exterior blinds, roof overhangs, screens, etc. If shading is not accounted for on east and west-facing windows in the heat gain calculation, the calculated cooling load might be significantly higher than the actual load. This could potentially suggest a larger unit be installed than needed. Manual J and most sizing programs have inputs to account for window shading.
 
Ducts – If the ducts are in the attic, the duct multiplier for cooling will be higher than for heating. If all of the ducts are in the attic, a reasonable cooling duct multiplier for well insulated and sealed ducts is 1.2, implying the cooling load calculated for the house needs to be increased by 20% to account for the duct gains in the attic. If not all of the ducts are in the attic, the cooling duct multiplier can be reduced. The multiplier should be increased if the ducts are unsealed or not insulated. The program recommends that you confirm that ducts in unconditioned spaces are connected, sealed, insulated, and supported. This will also keep the air temperature discharging from the diffusers at a nice low temperature, ensuring greater comfort levels.

For more information on heat pump sizing check out the new PTCS Heat Pump Sizing Reference Guide. We are also available to discuss any of your sizing inquiries. Contact us at 1-800-941-3867 or ResHVAC@bpa.gov with your questions.
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PTCS Training Videos
Your favorite PTCS training videos are now easier to find! The BPA Training YouTube page has been reorganized to help you locate and view videos of interest. Here, you can find:

  • PTCS Heat Pump Sizing
  • Duct Sealing Admin/Sales
  • Heat Pump Admin/Sales
  • Prescriptive Duct Sealing*

*Don't forget, you can earn a prescriptive duct sealing certification through our Virtual PTCS School. Contact us at ResHVAC@bpa.gov for more information.
BPA.gov Energy Efficiency Website Refresh
The bpa.gov Energy Efficiency and PTCS webpages are being refreshed. The new PTCS webpage "PTCS Essentials" will be organized by subject with hyperlinks to relevant documents, forms, and resources. To quickly locate questions and answers by subject new FAQs were developed for participation, resources, duct sealing, and heat pumps.

Contact us at ResHVAC@bpa.gov for more information.
Ask the Contact Center

Below are some of the things we can help you with at the contact center:

  • Registry won’t let you enter a job
  • Account needs to be updated with new employer
  • Typo in address or measure data need correction
  • New technician requires certification
  • Pending measure requires review and approval
  • First time using the registry and you need help

If you have any questions about the program, or proper procedures let us know and we will connect you with an expert. Contact ResHVAC@bpa.gov or 1-800-941-3867 for assistance.