In an ideal world our homes would be so well insulated that our
bodies and appliances would produce enough heat to keep us warm in
winter. Of course life is never ideal, and the chances are you don’t live in a passivhaus. But that doesn’t mean you can’t make the most of what you’ve got! Most
articles I’ve seen about cutting your heating bills tend to be a list
of things you can do cut energy use.
While this makes they all too
often overlook the benefit of being warm and aren’t always that
practical for many of us, in particularly tenants. As an economist
I tend to think heating your home as an optimization problem. You want
to maximise your comfort while minimizing what you spend to stay comfortable. How you approach this challenge depends very much on your living situation and how deep your pockets are.
In
this guide I’m going to try an lay down some practical advice for
cutting your heating bills this winter. I’ll start with the best option
for tenants, then home owners and finally look at home lovers.
The tenant’s guide to lower heating bills
Years
ago I rented a cold and damp basement flat in London. It was an error
from the minute I signed the lease. London is dark enough if live in a
penthouse so below ground is just horrid. On top of this indignity
the house was cold and a little damp. In particular there was a sash
window that had suffered so much subsidence you could fit your hand
though the corner when it was closed.
If this had been my house I would have fixed that window, but as a tenant my best bet was piece of £5 piece of window film.
Now if you tell a passivhaus engineer you’re using window film as
secondary glazing they’ll laugh themselves silly. But as a tenant with a
terrible window and crappy landlord it was a super solution, cutting my
heating costs and making my living room much more comfortable.
As
a tenant you’ve got very little incentive to invest in improving
someone else’s home. So you’re best bet is do anything simple you are
allowed to and then focus your attention on taking better control of
your heating. I’m going to give you three strategies you can use
to reduce the amount of energy your heating system uses. None of them
are ideal, but some mix of the three can normally save you a lot of
money with a limited impact on your comfort.
1. Turn down your thermostat
Have you ever heard that ‘reducing your thermostat setting by 1°C (1.8°F) can cut your heating bill by 10%’? That’s a ballpark figure, but there is actually some solid science behind it.
A home loses heat in two ways. Conduction through the fabric of its
walls, floor, roof, windows . . . and ventilation when hot air squeezes
through gaps under doors and out windows. Both conduction and
ventilation losses are a function of the difference between internal and
external temperatures.
That difference is measured in what are
called heating degree days. And for every 1°C (1.8°F) you reduce the
internal temperature of a building the number of heating degree days
falls by around 10% (see
below).
No,
I’ll admit that this is not my ideal solution, because it involves
tolerating a colder house. But its worth getting your head around. If
you want an example of someone taking this seriously and slashing their
energy use check out David King’s Sustainable Energy Without the Hot Air.
2. Time your heating wisely
The
key thing to remember about heating is that you only need rooms to be
warm at certain times of the day. If where you live has superb
insulation then you can maintain a steady temperature throughout the
day at low cost, but if the insulation is poor you need to get smart
with the controls. The graph below gives an idea of how someone who works in an office might program their home heating during the week.
By
allowing your home to chill out when you are asleep, and at work, you
will reduce the heat loss and hence the bill. The key to getting this
right is to ensure that things are timed well, so that when you wake up
or return home it isn’t to a cold house.
3. Zone your home sensibly
Just
like you don’t need heat equally throughout the day you also have
different needs in different rooms. For example it’s quite nice to have
a warm bathroom and living room, but bedrooms, hallways or dining rooms
might not need to be warm.
In my home we achieve this with
thermostatic radiator valves that regulate how hard each radiator works.
But there are also really high tech controls these days like the
Honeywell below, or there is always the old school method of just
turning of the heaters in certain spaces.
As
a tenant taking tight control of how much, when and where you heat is
about your best option. Throwing on an extra piece of clothing or
cuddling up to a loved one are always a decent option too. For more
info check out this video. If
you are lucky enough to own your own home these tactics remain useful,
but you can also work to improve the fabric of your home, as well as its
heating system.
The homeowner’s guide to lower heating bills
One
of the hilarious things about first buying a home is the realisation
that you could just get drunk one night and paint a huge mural on your
living room wall. For some reason this desire quickly subsides and
people end up painting everything magnolia. I digress. The
point being, if you’re lucky enough to own your own home you’ve got a
lot more options. In this section we are going to look at the cost
effective improvements you can make to a house. This is a bit of a
piecemeal approach, but handy if you are on a budget.
1. Use a cheap fuel source
It
bothers me a lot when I see people buying electric heaters during a
cold snap. That’s because people are largely clueless about how
expensive electric heating is. And sometimes they could be heating a
house for the money they’ll spend heating a room.
This graph below show’s how expensive a unit of usable heat is in the US.
As
you can see, both electricity and heating oil are expensive relative to
natural gas. For slightly newer data the EIA provides a spreadsheet
American’s can use for comparison. The situation is very much the same in the UK, with electricity costing three times as much as gas.
2. Insulate, insulate, insulate
When
you improve your home’s insulation you ensure that you get more comfort
for every unit of heat you pump into it. In many cases insulation can
be a superb investment, paying itself back in saved energy in a matter
of years. Of course this isn’t always the case. The graph below
shows you how diverse the payback rate can be between different
insulation technologies.
Now
these examples are based on technology prices, building standards and
energy costs in the UK, so don’t take them too literally for your own
situation. What they do show is why governments are so keen of loft
insulation, cavity insulation and draught proofing. This is also handy
information to have when someone tries to sell you windows, because
salesman talk a lot of rubbish about the payback on windows.
3. Upgrade an ageing heating system
Personally,
I only think you should turn your attention to upgrading your heating
system when you’ve already had a decent go at improving the fabric of
the building. By that I mean you’ve made all the cost effective
improvements to insulation and draught proofing that make sense.
Where I live in the UK a new boiler pays itself back in around 10 years,
depending on what you’re switching from. So it makes most sense to
switch if you are facing a hefty repair or if your old boiler is really
inefficient.
One of the main problems people face in this
situation is underestimating the full cost of a new heating system. The
graph below is some data I put together for an energy company in the
UK. It gives you a rough idea of how to price the full cost of the
equipment, installation labour and extras.
Looking
at each technology option in isolation is often how people think about
insulation, draught proofing and heating. And although this is ideal it
makes sense for people on a budget, as you want to get the most bang
for a limited buck. But if you love your home and intend to stay a little while you might want to upgrade how you think about heating bills.
The homelover’s guide to lower heating bills
Oscar Wilde once said that ‘A cynic is a man who knows the price of everything, and the value of nothing.’ Up
until now we’ve taken a rather a cynical approach to heating bills.
We’ve focussed very much on what you can do to cut them, without dipping
to far into your pocket, but paid little attention to the value of a
comfortable home. But there is another way to think about this. Take one step inside a super insulated passivhaus in winter and you’ll get it.
Comfort is king!!
A house
that is draught free, has no cold spots, doesn’t overheat and maintains
constantly fresh air is truly valuable. And though you might never live
in a passivhaus this everyone who loves their home should think about
heating. If you can make investments in the fabric of your home, or its
heating system, that improve your comfort, then any reduction in heating
bills is more of a bonus.
So what’s a passivhaus you ask? A
passive house (passivhaus) is a super insulated energy efficient home.
It is built using ultra high specification insulation, triple glazed
windows that face the equator to maximize solar gains, and is so air
tight it uses a ventilation system to keep the air fresh. It needs just
15 kWh/m2a of heating, much of which can be gained from heat recovery in the ventilation system. To
give you some perspective this is around a tenth of the heating needs
of a typical modern home, cutting bills to almost nothing.
Now
I must say I really love that graphic, because it reminds people that
the heating demand of a home is really just a function of how much heat
it leaks. But for a lot of people it’s just a bit too much science.
This beautiful shot from the first passive house retrofits in New York really nails it though.
Now certain people get very excited achieving a passive house certification,
but its really just a standard. And you don’t have to meet the
standard to have an incredibly comfortable home with low heating bills.
But the way of thinking can really benefit everyone.
The fabric
first approach encourages people to dig right down into air tightness,
thermal bridging, U-values . . . and brings with it a requirement for
high quality work. And even if you can afford to spend what is required
for a top end retrofit, you can really benefit from this joined up way
of thinking about things.
Bring in a professional
If
you’re serious about upgrading the comfort of your home then I’d
suggest you get a professional. Not only does serious energy efficiency
require a whole lot of science and practical experience, it also means
knowing tradespeople capable of providing quality work.
You may be able
to carry that off if you are really interested in the subject, but for
most of us a pro is where its at. The first step in this process is to have a serious energy audit done.
This should involve a physical inspection of your property, the use of
tools like cameras, thermal imaging and blower door tests, and a
software analysis of your home.
Here’s a checklist from the US Department of Energy about what to look for:
The
big benefit from a proper energy assessment is that it gives you a
baseline to gauge which improvements will benefits you most. In
contrast to the cut and paste approach of doing individual jobs in
isolation having a full assessment will give you perspective about what
your home’s strengths and weaknesses are.
A good energy assessor
will then suggest some solutions that are sympathetic to your home and
your budget. You should be under no obligation to do any work or feel
locked into any particular company. Finding the right professional is
half the challenge. So you should research if there is a certification or directory local to you.
After
you have an assessment I always think its a good idea to take a breath
before committing to too much work. If you are planning a few bits of
work make sure they occur in a logical sequence and are timed so they
don’t mess with your life too much. But most of all don’t forget
that a warm home is a valuable one. This does extend to the value of
your home, but what I really mean is it can improve how you live. This
is value that extends far beyond any heating bill.
http://www.theenergycollective.com/lindsay-wilson/2275699/beginners-guide-lower-heating-bills-tenants-owners-and-homelovers
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