I took a bit of good-natured ribbing from my builders for not
choosing a "higher-end" type of siding. They were more used
to putting Hardiplank and such on retrofit homes! I went with
generic vinyl because it's zero-maintenance, more resistant
to water infiltration, and I can *take it apart* if I need to
replace a piece or access surfaces underneath. Plus, the
flexibility of the vinyl makes it easy to feel exactly where
the strapping sits from outside -- knowing that is important
if anything ever needs to be attached to an exterior wall.
A peek under the covers shows the foam, strapping, and
rainscreen gap structure of the new wall. The bottom slot is
protected by bug screen all the way along, and the top exits
into the vented soffit areas under the overhangs.
Because of the sill slant across a much thicker wall, a standard
80-inch storm door was too short for the outer opening. A simple
extension attached to the bottom closes the gap and makes it
all tight.
The extension piece is somewhat delicate; please avoid kicking it.
These short vertical duct extensions bring the HRV intake and
exhaust above expected snow line. The exhaust here is the only
service penetration not sent through the special window-blockoff
panels; it repurposed the existing holes for the old heating-oil
fill pipe and vent. There really wasn't any better location
location for the exhaust anyway -- downwind, some distance
away from the intake, and everything on the back of the house.
Up where you can't really see it, an S-5! snow-guard was installed
on the shed-dormer roof section after the first winter with big
chunks of packed snow thudding down onto everything underneath
as it slid off the metal roof panels. It's worth protecting the
infrastructure along the back here, whereas it doesn't matter
so much in the front. That may get a guard someday too.
Many people hear "house" and "energy" and immediately ask
if photovoltaic played a part in the retrofit. Here's one of
the main reasons that answer is NO. I like my trees. This oak
at a minimum would have to come out to get nearly enough
exposure on the roof, and even then the array size, let alone
its active hours, would still be rather limited.
So no "net zero" or the like here, short of trying to do CHP
with methane from the swamp. For now it's nicer having
the summer shading and simply using less from the grid.
The outdoor guts of the heat pump system. It's a 1.5
ton (18,000 btu/hr) unit, which is ample capacity for
this house after the deep energy retrofit. These newer
horizontal-flow type units need surprisingly little wall
clearance at the air intake, and the fan blows waste air straight
away from the house instead of upward against the wall and
overhang. Both refrigerant pipes are separately insulated
and then an extra insulating and UV-protective blanket
wraps around all that. An amusing feature is that the roof
of the little hutch over the unit was made to match the main
roof, utilizing some of the standing-seam panel cutoffs.
A fortunate discovery about the Daikin unit is that it uses
electronic pressure sensors, allowing basic measurement
of high-side and low-side pressure without having to open
the piping and put gauges on it. This allows a quick
checkup on charge status, using nothing more than a
voltmeter and a pressure/temperature chart for R410A.
Now, it would have been nice if Daikin had just made the
pressure readings directly available at the controller...
A simple framework with wire mesh replaces the useless
condenser-coil grille, giving better protection and enough
distance from the coil to not interfere with defrosting.
Instead of generic splash pads, these small pits are only a
couple of feet deep but allow most normal downspout runoff
to soak right into the soil well away from the foundation.
They're constructed with larger rocks at the bottom and
working downward in size toward grade level, to allow plenty
of free space near the subsoil. In heavy rain, the pits
fill up and gently overflow at the downhill edges, but
only for a few feet beyond before the sandy soil there
easily absorbs the rest.
The local power company (RMLD.com) offers time-of-use billing,
which can drastically reduce electricity bills when judiciously
used. Peak hours under this plan are are noon - 7pm on weekdays,
and an energy-efficient house can generally *shut down* its
most power-hungry appliances (including heating/cooling!)
for that entire time and easily ride through.
A meter changeout is required to make this work. You can see
this one alternating between the peak "A" kilowatt-hour reading
and the off-peak "B" one (which is active now).
Simply faced with a kick-board after door re-installation,
the narrow space behind the stoop had no protection against
water ingress from splash or wind-driven rain. One piece of
metal coil-stock later, it does.
This was a problematic area in general due to the need to cut a
big slot in the stoop to accomodate a continuous layer of new
insulation over the sill area. This whole door is still a
little ugly in general, but it will get finalized someday.
The small bits of black gaffer's tape stuck on to various
surfaces provide a consistent surface type for taking
infrared temperature measurements across different types
of objects and materials. Metals and foils are especially
problematic in that they behave like infrared mirrors
rather than radiators. This is easy to see from watching
an image of one's own body move against glass, foil-faced
foam, and similarly IR-reflective materials. Are we
measuring the object or the room around it? The tape
helps even out that playing field.
One wire between inside and outside was eliminated when the
town installed the radio-based meter reading transponder. The
area around the incoming pipe and meter and pressure regulator
required a bit of crazy adaptation in the insulation, both to
fit the minimal space available and to keep foil-faced products
away from the radio sender to avoid possible interference.
This separately metered subpanel feeds the HVAC system and
HRV, allowing fairly accurate measurement of electrical energy
used for heating or cooling -- in winter, that's the post-upgrade
equivalent to gallons of heating oil burned.
Four out of six basement windows were replaced with these
insulated and sealed block-off panels, constructed of wood
and XPS foam and an outer skin of PVC adapted mostly to the
original frames set into the masonry. (see diagram) Any
needed service penetrations pass through specially-constructed
holes in these, rather than arbitrary points in the walls.
The two basement windows kept as windows got reconditioned and
additional panes added, and full weatherstripping to be leakproof.
This one also gets a quick-n-dirty adapter inserted when the
dryer hose is dropped outside during a laundry run.
After intercepting the retrofit builders when they were going
to simply throw the extra polyiso foam in the dumpster, I used
the saved pieces to add a new layer over the existing styrofoam
on the basement block wall that had been in place before I took
ownership. Surprisingly, even after giving some of it away the
remaining project scrap went around three-plus out of the four
walls, up to about here, with only three additional 4x8 sheets
needed to complete the layer behind "infrastructure row".
The pieces are simply glued to the old surface with Dynaflex
caulk, and a "footing" around the base supports the vertical
layer and helps insulate the edge of the slab a little way in.
It's all air-sealed to stop convective loops from the cold
wall behind everything.
The sill-area spray foam job originally covered some of the
pipes feeding the laundry hookup, entombing them in foam but
touching the concrete wall behind it. This could be bad in
cold weather, so all this crazy complexity worked around
behind the pipes is to bring them back into the conditioned
space and get some insulation against the wall behind
them -- even the paltry half-inch helps, as the pipes will
now remain at the interior basement temperature with no
risk of freezing sections.
With the extra insulation layer completely hiding almost all
of the original foundation cinderblock, this one small window
into raw concrete allows monitoring the wall temperature with
an IR gun. The surface is actually a concrete plug installed
through the block where an old laundry grey-water line used to
run out to the backyard, but Title 5 obviously wouldn't allow
that when the septic all got rebuilt 20+ years ago. The plug
connects directly to the above-grade masonry and gives a pretty
good indication of how cold the inner surface of the wall is
trying to be.
This air intake duct will spend a lot of time being cold, and
thus a condensation magnet for interior air. This moisture
is basically unavoidable but needs to be managed if present.
The outer cladding around the fiberglass duct insulation is
completely sealed off at both ends, and the PVC pipe coming
from outside gets a tiny little drip flange made from aluminum
tape -- to keep any water runoff clear of the wood and let it
fall onto wet-insensitive materials below.
Yes, this falls into the "lessons learned" category...
More sensitive than the "whole house manometer" that preceded
it, this also gives a visual indication of pressure change trends
over time. It's simply a sealed box with a membrane, connected
through a tube to the outdoors, to show whether the interior is
under generally positive or negative pressure. Its relatively
slow response ignores transient changes like opening doors.
Installed a few years before the retrofit, this has a plastic
tank with a fiberglass pressure cladding and a LIFETIME
warranty. The inner tank is insulated with two-inch polyiso
foam, and it's one of the most efficient resistance-electric water
heaters available. Sales of these are apparently less common
in the northeast than in other parts of the country, which is
rather perplexing.
There's also a bit of hackery on top using Reflectix, to lessen
heat loss from the piping.
One of the earlier experimental components, done to rescue an
originally somewhat decrepit and very leaky door. Mostly of
scrap wood and XPS foam free from a local lumberyard where
they couldn't sell some of the more banged-up pieces. The
threshold rail assembly has a piece of Azek on the bottom to stop
moisture from the concrete, and the rest of the sill structure
fills in where some of the original doorframe was missing at
the bottom. The threshold also forms part of the complete
weatherstrip surround that seals against air leakage. The door
gets squeezed slightly against the weatherstrip with a simple
compression-bar arrangement inside.
A snug-fitting piece of polyiso foam dropped down against the
door continues the insulation "footing" past it, covering the
area of slab closest to the outdoor-temp bulkhead opening.
Now considered a big no-no in the HVAC industry, the original
ductwork system used panned joists for the return plenums.
The configuration is somewhat atypical, with the returns
located at the outer walls rather than the supply registers.
With the low airflow required the panned returns work just
fine and didn't need any upgrades, and having the supply
ductwork at the inner core of the house keeps it all
nice and cozy with less runout and perimeter heat loss.
Since return ducts from the main floor are just stud bays in
the walls anyway, putting the retrofit insulation outside all
of that eliminated a *huge* source of heat and air leakage.
The front door used to just sit across the ends of the floor
joists. Some additional framing was added here underneath
the door frame, to give a solid bed of wood for the sill area.
The heat-recovery ventilator brings in fresh air and exhausts
stale interior air, capturing beneficial heat or cool from the
outgoing stream and pre-conditioning the incoming air through
an aluminum exchange core. Especially effective in winter when
the interior/exterior delta is largest. Even at only 70% rated
efficiency this unit helps a lot -- the coldest incoming air
observed with zero-degree outdoor temps was about 45F
before being injected into the main air system. It still means
somewhat cooler air is coming into the house, but results
in far less overall heat loss than with a direct vent.
A simple ductwork assembly that collects stale air from three
different areas of the building -- attic, main floor, and basement,
combining them into the ventilation exhaust stream sent outdoors by
the HRV. Each pickup can be independently closed off if needed.
Including an attic in the ventilation system is somewhat unusual,
but in this case it completes part of the circulation loop for
the second floor. The duct comes down the old chimney flue.
This box brings together the minor wiring changes and additions
needed for the auxiliary thermostat and control links between
the air-handler and HRV. Switches allow enabling or disabling
parts of the system as needed. The big red LED shows when
the resistance electric heater is on, or would be on if its power
switch is enabled. A safety shutoff from the condensate
pump also connects here.
Ducted air handler, designed in a form factor compatible with
typical furnace replacement. The fifty-year-old oil burner
used to stand here, and it was relatively easy to tie the new
system into the existing ductwork which design calculations
showed would be entirely adequate for the expected airflow.
Obviously the front cover needs to be on this opening for
proper operation; this is just to display some of the innards.
To the left of the coil is one of the two electronic expansion
valves in the system, which along with a variable-speed
compressor allows exact computer control over output
capacity for the best running efficiency.
The backup resistance heater sitting out was removed for summer,
to keep it out of the high-humidity airflow right off the coil.
Rarely seen in typical residential systems, this duct hatch was
added later after the original installation. It allows viewing and
cleaning the underside of the coil, which is where dirt is most
likely to accumulate in the first place. Early signs of leaks
or drainage problems would also likely show up here, before
manifesting as an actual leak.
The realization that the bare metal ductwork was radiating
significant heat away toward the colder basement prompted a
good use of some leftover half-inch polyiso. There was just
enough left after the main retrofit job to cover most of the
main supply run and distribution box, cutting way down on heat
loss and sending more of it upstairs where it belongs. Also
helps reduce condensation potential during cooling season
by keeping interior air away from the cold metal surfaces.
Summer cooling and dehumidification needs to include the
basement, to both keep it dry and lessen cooling load by taking
advantage of the fact that the air is already cooler there
to begin with. This isn't needed in winter, when the basement
can freely run closer to the natural 55F ground temperature
and doesn't need to be specifically conditioned. By changing
between a solid or open end-cap on the duct and opening or
closing the supply register at the other end of the basement,
the space can be mostly included or excluded in the air system.
The open cap is ducted down to the floor to pick up the cooler
air that accumulates near slab level.
Typical under-door sweeps or gaskets (if installed at all)
wear out quickly and usually provide a poor air seal that leaks.
A simple addition to the sill gives a seating surface where
continuous weatherstripping can compress and completely seal
around the opening. A small downside is some care needed
when stepping over it.
Yet another window experiment, a precisely cut piece of
cardboard (or something) wedged into the window trim can
in theory reduce the effects of small convective loops that
bring cold air down off the window surfaces to mix undesireably
with interior air. It's not an inside storm, but should help
keep chilled air a little more contained away from the living
space. It remains to be seen whether this will actually help or
just cause a condensation mess on the windows themselves.
Unlike most folks, I kinda prefer it on the dark side when
hunkering down for the winter...
A ratty assortment of blinds and drapes was replaced with a
uniform, simple but effective set of shade assemblies made from
Reflectix radiant barrier. Sold in large rolls at HD usually to
install under rafters to stop radiant transmission into attics,
it is completely opaque, weighs nothing, and is easy to cut to
the required sizes. A couple of light wood battens and hooks
are all that's needed to complete each window.
The Reflectix has a slight natural twist, so each shade gets some
small object to hold the left corner against the window when down.
That's really the brand -- although now the Serious Energy
product line has been re-absorbed by their original parent
company, Alpen. These are fiberglass-frame, dual-pane
single-hung units with a "heat mirror" membrane and argon
gas fill, boasting a unit-average R-value of around 5 or 6.
The most transmission is clearly at the frame, despite the
design efforts to minimize thermal bridging at those areas.
They seal well (after some minor post-installation fixups)
and are fairly condensation-resistant.
Twelve windows were replaced with these new-construction
units, and two of the original windows were walled over
and simply eliminated.
This shows the basic construction of the old house walls (and
their hideous color) versus the retrofit assembly. It was all
stripped back to the bare plank sheathing. The model shows
the essential build-up from there -- tyvek, one layer of polyiso
foam taped at the seams, a second layer of polyiso with joints
staggered away from the first layer and also taped, and finally
the strapping and screws holding it all together structurally
lagged into the original framing. The siding goes onto the
strapping, leaving a rainscreen/ventilation gap behind to
promote drainage and drying.
Sometimes it's hard getting around to cleaning up little piles
of junk that have been sitting there for years. It's always a
delicate balance between saving possibly-useful stuff and
getting overwhelmed. Keeping materials stock came in really
handy during the retrofit, however, as many stored items were
"neatly used up" to build more beneficial subsystems.
The living space is well-instrumented for interior air quality.
In a tight envelope with the ventilation shut down, carbon
dioxide levels will slowly climb. Humidity measurement
is a little less accurate, seen in the difference between
the RH displays, but is enough to warn if it wanders outside
a desireable range.
Relative humidity % can be mapped on the psychrometric chart
to determine grains per pound and what will happen when a
given volume of air is heated or cooled. A rough guess at
the energy required can even be made from the equations.
More than just a thermostat, it's more like a small data terminal
to communicate over a simple two-wire link to the HVAC system.
Includes typical time and date based programming capability,
including weekday/weekend splits and full control over on,
off, heat, cool, and setpoints. System features and settings
are programmed here using special service menus. The display
also provides some minimal system diagnostics and sensor
readings, but that set of data could be far more comprehensive
than Daikin sets it up for.
Unlike the over-rated "nest", it does NOT talk to the internet.
The chart below details some of the maintenance-menu items
that can be displayed to see direct sensor values.
Allows independent control of the resistance electric "toaster"
heater in the air-handler, for measuring system heat output
directly in kilowatt-hours without having to guess at the
heat pump's coefficient of performace (aka additional heat
from outdoor "magic fairy dust"). Direct heat energy versus
degree-day figures is one way envelope heat-loss stats can be
calculated, with the downside that it's a more expensive way
to heat over the measurement periods.
One of three collectors for exhaust air through the HRV. This
picks up more or less from the kitchen and bathroom areas, even
when the basement door is closed. It was far easier to do this
than start punching ductwork through the interior walls.
Go up and turn left, left, left toward the attic ladder
During the overall project the otherwise unusable attic was
cleaned out, the old insulation removed, and a pseudo-floor
installed to facilitate access (using a lot of the scrap
cut-offs from building the roof deck). It now mostly serves
as storage for various construction materials. With the
thermal envelope moved above the roof sheathing, there is
no longer any real need to isolate the attic from the rest of
the house and the hatch can simply stay open.
Climb up and look around for more fun attic facts!
The old furnace chimney was disassembled down to here, and the
flue repurposed as a duct chase for one leg of the HRV pickups.
Airflow is taken from the ends of the attic, giving a full
circulation path from the second floor via the hatch and/or
kneewall areas.
While the builders were careful to drive fasteners for the new
roof deck into the original roof rafters, it's hard to get the aim
exactly right through four+ inches of extra layers and screws
do miss sometimes. These were generally corrected at build time
but some of the temporary foam fasteners start from underneath
the final deck layer and couldn't be re-driven. Some of the screws
form tiny thermal bridges through the foam and the points get a
bit cold in winter, but not enough to drip condensation or
affect the overall insulation value.