Wednesday, March 31, 2010

Renewables


The biggest outstanding question in my head, and probably always has been since we decided on the structure type, is the heating. I'm convinced on the comfort of Underfloor, and happy with the idea of MHRV. The problems start once we get into sourcing the energy.

Currently, you can probably supply fit & commission a condensing oil burner & tank for about €3,000. This then has a high constant outlay over the lifetime of the burner, but low capital cost.

The other option is a heat-pump. However - the area to be heated in our house is significant, and so a single pump (on the premise of single-phase electricity supply) would not cut it - certainly for a traditional build. So - I can either install 2 pumps (say 14kW + 11kW), install Oil and a single pump 16kW, or and what I had been thinking, is to chance a single 16kW with an immersion coil and bet on the insulation finish on the house to be enough to reduce the load.

I've been in an ICF house that was about 20% smaller than mine in area, but heated with a single 11kW A2W pump the inhabitants were very happy, but ran it at 18C and the property had a much smaller glazing area. Thats what pushed me to a single 16kW pump and hoping for the best.

A potential supplier modeled the heating requirement (subject to massive assumptions and average weather) and it looks like once we go below 0C we need backup from the immersion coil.

On top of all of this is solar. 'Free' energy for nearly 3 seasons sounds like a great buy, but with the Heat Pumps able to operate at night & heat a buffer during these times it's saving the night-rate electricity - currently about 8c/h.

The only thing thats not making me pull away from all and any renewables is that we will be living there long enough for the bigger ROI plays to pay out. Anything around a 20 yr horizon isn't too daunting.. more than that and I have to think hard. You can guess where I think our ROI will be!

Tuesday, March 30, 2010

A River runs through it


On site this morning to have a look at the proposals to work-around the springs right where our basement is planned to go. First - and part of the plan - we open up the side lane and put down some 4" stone for access. Second, we start clearing out some of the clay lower down and see what that does to the spring - it may move the water egress further downhill (good) or leave it as it is (not as good). With the latter we'll have to add some 6" drainage pipe covered with drainage stone and lean mix, backfilled.

The other issue to come to light is that the fall of the shale substrate goes away from the surface lower down. This will be a problem as the foundation needs to be bedded into it, and either we pull all the levels down (bad) or fill-in where the slate has fallen off. Either way is more expensive for time on the machinery and of course filler stone. Snow and Rain today makes doing anything on the site impossible, with our engineer getting stuck above his calves and still sinking right in the middle of the field. But there is always a solution, and while it will add a few grand onto the cost of this section the only other alternative is to fill it all in and stay where we are! And it could have been much worse - it could have been solid rock under the topsoil. Hopefully by the end of the week we'll have a much better idea on how it will play out.

Taking bets that when we drill the well we won't find water!

Monday, March 29, 2010

To blog?

Ok - so my initial feeling on blogging was not to, and so until now I maintained that. However - a realisation that blogging isn't for others, but for myself has made me re-evaluate that decision, and now that finally we have started the build it's the appropriate time to see if I can maintain this. Since I've never kept any type of Diary, this may be a discipline too far. But since I advised others to blog some of their adventures and ignore those who dislike the idea, I suppose I should follow my advice and hopefully have this to look back on once the pain is forgotten.

To recap on the last year we have had to:

  • Obtain Planning Permission (obtained June 09)
  • Apply for and be accepted in principle for a mortgage in this climate.
  • Select a contractor for the structure (decided Dec 09)
  • Obtain right-of-way to access the site (obtained Jan 10)
  • Decide on contractors for other major items in the house (ongoing)
  • Get an excavator and operator to dig (Mar 09)
As of Mar 19th we have offically started, with the excavator breaking ground. There is a massive amount of earth to be removed with the split-level over basement design requiring digging into the hillside. As of today we have excavated as per the picture.



Nothing is easy - already only 1 1/2 weeks into the build the changes and problems start.. first off the heating system may get a good bit more expensive due to the floor area of the build... that or we change tack and go with dirty old oil. Second and more immediate is while digging out the lower section for the basement we've hit 2 water springs that subsequently flooded down the road - the picture below is after we cleaned up a lot of washed out silt. The result of that is we may have to move the house back 4 feet or so and drain off the springs.