Passive House - why bother?!

just do it

From Guidance Note wrote:

1.2 RENEWABLE ENERGY
TECHNOLOGIES
1.2.1 This section gives guidance on the
minimum level of renewable technologies to
be provided to show compliance with
Regulation L3(b). The following represents a
reasonable minimum level of energy
provision from renewable energy
technologies in order to satisfy Regulation
L3(b):
- 10 kWh/m2/annum contributing to energy
use for domestic hot water heating,
space heating or cooling; or
- 4 kWh/m2/annum of electrical energy; or
- a combination of these which would have
equivalent effect.
For the purposes of this Section, “renewable
energy technologies” means technology,
products or equipment that supply energy
derived from renewable energy sources, e.g.
solar thermal systems, solar photovoltaic
systems, biomass systems, systems using
biofuels, heat pumps, aerogenerators and
other small scale renewable systems.

So PV spec'ed to supply 4kWh/m2/annum satisfies Part L.

just do it

The cost of energy supply directly off the grid for my 236m2 house based on PHPP should be:
Heating 13.5 kWh/m2/annum -> €477.90
DHW 27 kWh/m2/annum -> €955.80
General 36.5 kWh/m2/annum -> €1,292.10

TOTAL €2,725.80

(assuming 15c/kWh) and standing charge not included.

fclauson

just do it wrote: »

So PV spec'ed to supply 4kWh/m2/annum satisfies Part L.

Do you have a HP or a certified wood only stove - this can contribute - do not produce too much electric as currently (may change in the autumn according to one rumor) there is no feed in tariff for the excess

just do it

fclauson wrote: »

Do you have a HP or a certified wood only stove - this can contribute - do not produce too much electric as currently (may change in the autumn according to one rumor) there is no feed in tariff for the excess

My energy assessor who did the PHPP in 2012 had also done a cost analysis on a few different options and comparable payback periods against each other. What they weren't compared to was electricity bought directly from the grid. The 3 options presented had paybacks vs electricity of 40-120 years :yikes:

I'm coming to the conclusion renewable energy sources for heating and DHW in passive houses are a waste of money. Unfortunately not to install them is breaking the law regardless of the arguments presented in articles in passive house plus. At least with PV panels they tick the regulatory box cheaply, are virtually management free, can be added to, and there is major investment going into batteries, possibility of a feed in tariff etc

fclauson

you should have a word with you local building control officer - the renewables numbers are not mandatory (i.e. the TGD give them as how you show defacto compliance) but the legislation states (Part L 3 (b) )

providing that, for new dwellings, a reasonable proportion of the energy consumption to meet the energy performance of a dwelling is provided by renewable energy sources;

There is an argument - and some have argued that in a PH the words "reasonable proportion" means something different to a "normal" house

Strolling Bones

fclauson wrote: »

There is an argument - and some have argued that in a PH the words "reasonable proportion" means something different to a "normal" house

Someone smarter than me described building regulations as a splicing of technolgy and law. Both ever evolving.

Obtaining an agreement with a BCO would be a wise move in this case.

just do it

fclauson wrote: »

you should have a word with you local building control officer - the renewables numbers are not mandatory (i.e. the TGD give them as how you show defacto compliance) but the legislation states (Part L 3 (b) )

providing that, for new dwellings, a reasonable proportion of the energy consumption to meet the energy performance of a dwelling is provided by renewable energy sources;

There is an argument - and some have argued that in a PH the words "reasonable proportion" means something different to a "normal" house

Yeah, all this is background research with a view to meeting the building control officer . Decent debate on such things has really dried up on here :rolleyes:

fclauson

not sure if they are still on line but Passive House Magazine had an article by me followed up by some letters from a BCO saying what their view was

probably about 2 1/2 years ago

just do it

fclauson wrote: »

not sure if they are still on line but Passive House Magazine had an article by me followed up by some letters from a BCO saying what their view was

probably about 2 1/2 years ago

I've the hard copy

Shanaknocker

hi to all on this tread,
I have so many questions and need a some strong independent advice.
I am planning on building a new house, split level witch will be to Passive standards, ie U-values of 0.15 in most areas and triple glazed windows. I did not go down the route of Certification so do not have the PHPP done on the house. My intention is to get my house down to below 30kwm2. it will be concrete built 220mm with 200mm external insulation, passive foundation, and i hope a passive standard roof (waiting on contractor to get back with details)

Heating:
My issue is every company we talk to wants us to buy Heat pump with underfloor heating or a large KW heat pump costing a large amount.
My first intention was to go down PV route, and have electric immersion, MHRV post heater, and electric rads, but PV panels not up to scratch yet. I was also looking at a thermodynamic panel, which will give me 365 days of hot water and to use this hot water to heat a post water grill that is attached to my MHRV, does any know will the Thermodynamic panel be enough or will i have to go down the heat pump route. House is roughly 210m2.

I know some of you have passive houses and from what i have read you believe that HP with UF is the best approach, I want to reduce the initial cost, reduce running cost but still have a comfortable house (wife is cold blooded). I have been priced by two companies one selling a 6kw with rads in wet rooms and a heat coil. the second has a 11 kw system with UF and or rads. Will 11kw be too much and will be cutting in and out more frequently.

hoping for advice

Shanaknocker

just do it wrote: »

My energy assessor who did the PHPP in 2012 had also done a cost analysis on a few different options and comparable payback periods against each other. What they weren't compared to was electricity bought directly from the grid. The 3 options presented had paybacks vs electricity of 40-120 years :yikes:

I'm coming to the conclusion renewable energy sources for heating and DHW in passive houses are a waste of money. Unfortunately not to install them is breaking the law regardless of the arguments presented in articles in passive house plus. At least with PV panels they tick the regulatory box cheaply, are virtually management free, can be added to, and there is major investment going into batteries, possibility of a feed in tariff etc[/QUOTE

Did you go down the PV route and if so does it work, is it efficiant

fclauson

I have very simple advice - without doing the maths embedded in the PHPP matrix you will be unable to determine the heat demand of the building - and without that you have no way of determining the size heating system you need

So my advice - do PHPP calcs - pay very specific attention to your cold bridge junctions to ensure they are correctly modelled and built - and if you get all of this right you may as well get full Passive Certification.

Guessing at the size of you HP etc cannot be done without knowing the underlying facts

Shanaknocker

Fclauson, to get the PHPP calcs i probably need to buy the software?

fclauson

either get the s/w and go on training or pay someone to do the calcs for you

Shanaknocker

Fclauson, what heating system do you have, I think i read that you have UF. what size HP is operating that and what is the electricity cost

fclauson

I have 8kw HP - 2kw HP and 6 immersion
the immersion has run less that 30hrs in 3 years

UFH in a single zone (i.e. no thermostats at all) totally controlled by HP which measures outside airtemp to determine if it runs

approx approx €1/m2/annum heating and hot water bill

MicktheMan

fclauson wrote: »

I have very simple advice - without doing the maths embedded in the PHPP matrix you will be unable to determine the heat demand of the building - and without that you have no way of determining the size heating system you need

So my advice - do PHPP calcs - pay very specific attention to your cold bridge junctions to ensure they are correctly modelled and built - and if you get all of this right you may as well get full Passive Certification.

Guessing at the size of you HP etc cannot be done without knowing the underlying facts

^^^^^^
This

fclauson

MicktheMan wrote: »

^^^^^^
This

a bit cryptic ?

MicktheMan

fclauson wrote: »

a bit cryptic ?

Not at all.:) Just agreeing with and emphasizing what you said.

Calahonda52

Just to add to the good advice given already.

Shanaknocker wrote: »

hi to all on this tread,
I have so many questions and need a some strong independent advice.

What do you mean by independent?
Are you will to pay for it, from the rest of the post I think not.

Shanaknocker wrote: »

I am planning on building a new house, split level witch will be to Passive standards, ie U-values of 0.15 in most areas and triple glazed windows. I did not go down the route of Certification so do not have the PHPP done on the house. My intention is to get my house down to below 30kwm2. it will be concrete built 220mm with 200mm external insulation, passive foundation, and i hope a passive standard roof (waiting on contractor to get back with details)

Is it built or not
am, versus did?
Meeting the Passiv Haus standard, even without certification, is not like ordering a Chinese takeaway from a menu: 1,3,11 and the house wine.
You either meet the standard or not.

Shanaknocker wrote: »

Heating:
My issue is every company we talk to wants us to buy Heat pump with underfloor heating or a large KW heat pump costing a large amount.
My first intention was to go down PV route, and have electric immersion, MHRV post heater, and electric rads, but PV panels not up to scratch yet. I was also looking at a thermodynamic panel, which will give me 365 days of hot water and to use this hot water to heat a post water grill that is attached to my MHRV, does any know will the Thermodynamic panel be enough or will i have to go down the heat pump route. House is roughly 210m2.

IMO, this is a pipe dream

Back to my point of paying: you are looking at maybe a 400,000 euro spend here and are whinging about buying a piece of software which might set u back 200 euro delivered in a day or so
eg
http://www.passivhaus.org.uk/podpage.jsp?id=72

Shanaknocker wrote: »

I know some of you have passive houses and from what i have read you believe that HP with UF is the best approach, I want to
1 reduce the initial cost,
2 reduce running cost
3 but still have a comfortable house (wife is cold blooded). I have been priced by two companies one selling a 6kw with rads in wet rooms and a heat coil. the second has a 11 kw system with UF and or rads. Will 11kw be too much and will be cutting in and out more frequently.

These three points are not achievable simultaneously.

If you invest the capital now ( in meeting, or maybe even exceeding the PH standard as well as on good kit) then the running costs will be reduced.

Once oil goes to say 150 a barrel and interest rates go to 4.5% and inflation is at 6%, then running costs are going to be the elephant in the room.

Shanaknocker wrote: »

hoping for advice

Heres to hoping you take it:D

This is my only contribution to this thread