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General Description
I bought 25 Minster Road in October 2008. The previous owner was elderly and the property had not been updated for around 50 years. I carried out major renovation work: loft conversion, rear extension, all windows replaced, completely rewired and plumbed, roof membrane replaced, new kitchen and bathrooms fitted, garden room and sheds built. I incorporated a number of eco-measures: internal wall insulation on existing exterior walls, solar panels & photovoltaic cells, underfloor heating on every floor, dual flush toilets, argon filled windows, wood burning stove, recycled blocks for garden room, insulated front door, low energy lighting, A+ efficiency appliances, induction hob, reusing existing materials (e.g. knocked down internal walls to create patio), sedum roof on garden room, garden compost bin. Building work began in January 2009 and was substantially complete 1yr later.
Vital Statistics
The house is a 3-bedroom semi-detached property built in 1907, situated on the North side of a quiet dead-end street in East Oxford. It’s built in a popular Edwardian style, similar to others nearby.
Originally with lounge, dining room, breakfast room, kitchen and conservatory on the ground floor, I knocked these through into two large rooms. I rent out one or two rooms to friends or tenants, and use one room as an office.
About me and why I did it Taking on a ‘blank slate’ property gave me an opportunity to apply current approaches to eco-renovation. After several years living abroad, I was ready to put time and money into a project that required me to be settled for some time. Heating and power Wood Pellet Boilers I visited two houses using wood pellet boilers – 1. Grove House in East Oxford, which has room for a large pellet store, which automatically feeds into the boiler as required, with bi-annual pellet deliveries. 2. A small period property in Wootton, Oxon, the boiler requiring replenishment manually every few days (details from Environmental Change Institute). On balance, I decided that the hassle of refilling the boiler regularly, and the noise & disruption of a regular pellet delivery in a built up area (with narrow streets) meant this wasn’t my best option. In a large country property, with room for a pellet store, I might have decided otherwise. Ground Source Heat Pumps (GSHP) I visited Ice Energy in Eynsham, which has working Mitsubishi Air Source and Ground Source heat pumps to view and buy. In the end, I felt that the CO2 saved didn’t justify the cost, when compared to an efficient gas boiler. Had I owned a large field in the countryside, I may have gone ahead. Air and Water Source Heat Pumps In the end I opted for an efficient condensing boiler, with underfloor heating in every floor, solar panels and photovoltaics, efficient appliances and induction hob. Solar Panels I obtained quotes from Solar Solutions Direct (Eynsham), Oxford Solar, Oxford Ecobuild, Solartech (Buckingham) and spoke to previous customers. The best feedback was for Solar Solutions and Solartech. After meeting Solar Solutions at their site, I would have been happy to go ahead, but in the end went with Solartech, as they also installed Photovoltaics, which I wanted.
Solar Photovoltaics (PV)
I received a £400 grant for the solar panels and £2,000 for the PV from the Low Carbon Buildings Programme, which I understand is being discontinued.
Underfloor Heating (UFH) Carrying out a major refurbishment gave me an opportunity to install underfloor heating on every floor. I obtained quotes from Nu-Heat and Solartech. Independent advice indicated that since the parts for UFH are standard, best deals come from finding a reputable plumber to install the UFH, buying parts at trade price. I went with Solartech, who charged £4,800 + VAT to supply and install the UFH on three floors (two manifolds, 6 zones). In practice I do not use the UFH on the first or second floors, since the excellent insulation means heating the ground floor is sufficient. I have engineered floorboards in the kitchen, and carpets throughout the remainder. Tests carried out jointly by the UHMA (Under floor Heating Manufacturers Association) and the Carpet Foundation supposedly showed that carpet can work with UFH so long as its tog value is <2.5. My combined carpet and underlay has around 2.4 tog value; the UFH does seem to struggle a little, and I have had to turn the main UFH thermostat up higher (55 degrees) than originally suggested by the installer (48 degrees). Solartech embedded the UFH pipes in a sand / cement mix, which acts as a thermal mass and is supposed to be more efficient than other methods (e.g. aluminium plates which conduct heat up into the floor). Wood Burning Stove There is a choice between traditional and contemporary (e.g. Hwam / Morso / Westfire), and different types (woodburning, multifuel, boiler stoves). I visited Manor House Stoves (Garsington) & First Choice Stoves (Beckley). The former was slow to return calls and the latter - although helpful and able to clean the chimney – didn’t have what I was looking for, so I bought online (Hwam Vivaldi). This 4.5KW stove, although pricey, looks beautiful and produces impressive heat. Appliances I chose high efficiency appliances (recommendations from The Energy Saving Trust) and an Induction Hob over gas. Although gas is more carbon efficient that electricity, induction hobs use half the electricity of standard electric hobs and, combined with the PV and a renewable energy tariff, seemed like a more efficient solution. I installed low-energy lighting throughout (Low energy dimmable lamps are now available from Megaman). Insulation The existing walls consisted of two layers of standard house bricks with no cavity insulation. I looked into using internal and external wall insulation to improve on this. External Wall insulation Advantages are that it doesn’t reduce the size of the rooms, the bricks remain inside warm envelope and act as a thermal mass. Disadvantages are that it is usually more expensive than internal wall insulation, and can create ‘cold bridges’ in the corner of the house (I wanted to insulate the side wall externally, but not the front brick wall). Oxford Ecobuild quoted £7,200 for 25mm insulation of a 30sq m section of wall. Internal Wall InsulationIn the end I went for internal wall insulation on every external wall of the house (i.e the front bay windows and side walls on the ground & first floors) using 50mm thermal insulation board made of polyisocyanurate (PIR), bonded to plasterboard. These are produced by Celotex and Kingspan, among others. The builders did excellent work, mimicking every detail of the bay windows. We fitted cavity wall insulation into the new extension. Also worth looking at is Tri-Iso foil insulation. An excellent resource, detailing recommended insulation levels to achieve best practice u-values (the rate of heat flow through a building) for walls, floor, roofs etc is ‘CE184 – Practical Refurbishment of Solid Walled Houses’, produced by The Energy Saving Trust (details below). My approach to insulation was to use the most effective insulating material (e.g. PIR board) rather than natural materials - which have lower carbon emissions in production - following the principle that the embodied energy of a house (i.e. energy required to build it) is less significant that its ongoing lifetime energy costs. To minimise drafts, I replaced the front door - my builder built a new one, sandwiching insulating material between plywood, and incorporating double-glazed glass panels, mimicking the existing (and neighbour’s) door. I fitted a letterbox with double flap and ensured a tight seal under the door. Other Aspects Garden Room For the external structure of this new building at the bottom of the garden, there was an eco-dilemma of recycled breeze blocks (Natural Building Technologies – Enviroblock EV11, EV12, EV3) vs. single skin clay blocks (Thermaplan blocks). I took advice from environmental architects LimeGreenHorse.org (Phil) who recommended the former as, although they had higher embodied energy, were better insulators, and it’s the long-term effects that are more significant.
I bought the sedum roof from the company that supplied by the lawn.
MDF
Leaching is supposed to be prevented if MDF is painted or varnished. Formaldehyde-free MDF, e.g. Medite Ecologique is available from some suppliers (e.g. Timbmet), but is 50% more expensive. I used standard MDF kitchen units, but formaldehyde-free MDF or timber where budget allowed.
Non eco-friendly aspects I fitted several steel beams (which have high embodied energy); ‘goalposts’ in the lounge and rear extension, and also over two chimneys that had been removed. I fitted two saunas - one small (4.5Kw heater), and one larger for parties (6.6Kw). The former heats the house, and since only on for short periods, energy consumption is relatively low. Who did each part of the work?
Resources |
Solartech
I obtained two quotes for PV, and decided to go with Solartech.They
