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My Plan to Achieve Energy Freedom - The Road to Zero Energy Bills

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Comments

  • Registered Users Posts: 9,218 ✭✭✭ antoinolachtnai


    The heat pumps section there is incorrect as far as I can tell and is best disregarded. There is no differential pricing like this for incremental consumption of electricity.

    Not really. The cost for band DD includes the cost of standing charges. But the standing charges are a ‘sunk cost’. You have to pay them whether you have a heat pump or not.

    The correct cost to use for comparison is the cost per additional kWh consumed, ie the unit price the supplier quotes.


  • Registered Users Posts: 177 ✭✭ ercork


    Is 21c per unit not a standard enough price? Of course there are discounts available and one year offers and all that (think mine is 16c per unit) but in fairness to the SEAI they can't really cover all the possibilities.


  • Registered Users Posts: 9,218 ✭✭✭ antoinolachtnai


    ercork wrote: »
    Is 21c per unit not a standard enough price? Of course there are discounts available and one year offers and all that (think mine is 16c per unit) but in fairness to the SEAI they can't really cover all the possibilities.

    From a quick perusal 19.86c is the highest price in the market for an incremental unit on a 24h tariff. The SEAI price comes from an EU study that is not really relevant to pricing energy for heating.


  • Registered Users Posts: 3,027 ✭✭✭ randombar


    I'm still not sure if there is a return on heat pumps.

    Cost:
    Heat Pump cost €8,500 (€12,000 - €3,500 SEAI grant)

    Standard calculations are a 50% cost saving based on existing gas or oil.

    So I've you've a well insulated house (a requirement for HP) your oil bill could be in the region of 700/800 per year (using my own for figures). Adding a heat pump would save 400 per year. 21 years before you see a return? I know there are comfort considerations etc. but the HP cost needs to fall to 4 to 5 k or the COP needs to increase a good bit for it to be seen as a viable solution yet.

    @Conor20 just wondering how much the retrofit of UFH was per Sqm?


  • Moderators, Category Moderators, Motoring & Transport Moderators, Regional East Moderators Posts: 60,510 CMod ✭✭✭✭ unkel


    +1 GaryCocs

    I'm far from convinced "upgrading" to a heat pump system is wise, even with the huge subsidy courtesy of the tax payer and even if your house is already very well insulated

    I like the idea of it and moving away from fossil fuels to fully renewable energy is very important. But not at all costs. And certainly not it the cost projections do not hold in real life.

    11PM: 15kW o'clock!



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  • Registered Users Posts: 683 ✭✭✭ Bif


    GaryCocs wrote: »
    I'm still not sure if there is a return on heat pumps.

    Cost:
    Heat Pump cost €8,500 (€12,000 - €3,500 SEAI grant)

    Standard calculations are a 50% cost saving based on existing gas or oil.

    So I've you've a well insulated house (a requirement for HP) your oil bill could be in the region of 700/800 per year (using my own for figures). Adding a heat pump would save 400 per year. 21 years before you see a return? I know there are comfort considerations etc. but the HP cost needs to fall to 4 to 5 k or the COP needs to increase a good bit for it to be seen as a viable solution yet.

    @Conor20 just wondering how much the retrofit of UFH was per Sqm?
    Another aspect to consider is replacement costs...how long do they last v standard boiler?


  • Moderators, Category Moderators, Motoring & Transport Moderators, Regional East Moderators Posts: 60,510 CMod ✭✭✭✭ unkel


    Another aspect is when a heat pump goes wrong, that there don't seem to be that many options to have it fixed. While any plumber can fix a gas / oil boiler. A few threads about it in the forum recently. And a gas / oil boiler rarely goes wrong, in the first 10 years of its life anyway.

    11PM: 15kW o'clock!



  • Registered Users Posts: 1,211 ✭✭✭ vincenzolorenzo


    unkel wrote: »
    +1 GaryCocs

    I'm far from convinced "upgrading" to a heat pump system is wise, even with the huge subsidy courtesy of the tax payer and even if your house is already very well insulated

    I like the idea of it and moving away from fossil fuels to fully renewable energy is very important. But not at all costs. And certainly not it the cost projections do not hold in real life.

    I've been wondering about this too lately.

    New builds are very energy efficient and have a very low heat load. DHW is actually a bigger demand than space heating, and as this needs a higher temperature than space heating surely you're getting a low CoP? So new build owners are spending a small fortune to put in a heating system that needs to deliver a small total kWh compared to older housing stock?

    Although traditionally viewed as poor has anyone looked at storage heaters for new builds? Much lower capital cost, run at night rate electricity keeps running cost down. Not as cheap to run as HP but surely much better payback?


  • Moderators, Category Moderators, Motoring & Transport Moderators, Regional East Moderators Posts: 60,510 CMod ✭✭✭✭ unkel


    Good points. We are a family of 5 with 3 teenage daughters and we use lots and lots of (really) hot water. I wonder how efficient a heat pump is in doing that. You could of course do most of it during the cheap night rate electricity, provided you have a big cylinder (ours is 360l but the standard traditional cylinder is just 120l)

    As for space heating, I am using mostly electric heaters that actually make me more money than they cost me in electricity this winter :D

    11PM: 15kW o'clock!



  • Registered Users Posts: 480 ✭✭ mike_2009


    Agree about the points made about Heat Pumps. Although - Solar panels weren't "cost effective" 10 years ago, but are very nicely priced now. Efficiencies still improving too albeit slowly. Batteries will continue to get cheaper over the next 10 years and there are other forms of storage possible too (heat batteries).
    Heat Pumps aren't around as long or as popular as Gas/Oil boilers but these have peaked in terms of efficiency and price. Hybrid heat pump / gas / oil boilers are available today and over the next 10 years the number of heat pumps manufactured and installed will drive prices down and skillsets up. At least that's what should happen!
    I wonder about risks to gas/oil supplies but even our Electricity supply relies heavily on gas but in 10 years hopefully less so. If we have turbulent times ahead due to climate migration and national isolationism I wouldn't be betting heavily on an imported fuel. I'd even say electricity power cuts will become a regular occurrence given our current power sources and the lack of new capacity/retiring of old plants.
    Should each household hang onto alternate means of space heating / water heating but how far out do you go on that particular branch?
    Agree that if you're lucky enough to live in a newer house space heating is relatively easy compared to hot water. Night rate for hot water 1:1 is still affordable but look at all the taxes add to the Electricity bill, prices still rising. CO2 heat pumps are better geared to delivering higher temps but may not be suitable to the Irish Climate (higher humidity) from what I've heard. Still the idea of getting 3 or 4 times the unit of heat per kWh is attractive. Will it last 10 years though? With annual maintenance there's no reason it shouldn't last over 20 years if it's a good quality model from what I've read.
    Anyone have any hot springs near them they can tap into?
    Excellent points made by everyone here and thanks to the O.P. for his recent update - inspiring!


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  • Registered Users Posts: 7,757 ✭✭✭ Tigerandahalf


    When you look at the night rate above and the amount of wind energy being generated at night should we not see a push towards storage heaters?

    With so many people working from home they deliver a consistent stream of heat all from electricity at off peak times. Less pressure on the grid. They could also have batteries attached or battery storage somewhere in the house, allowing use during the day but off the night rate.



  • Moderators, Category Moderators, Motoring & Transport Moderators, Regional East Moderators Posts: 60,510 CMod ✭✭✭✭ unkel


    Yes we should. I'm having an eddi installed this week and intend to use it mainly to power 2 storage heaters, with night rate and with excess PV

    We have 3 people working from home in the house every day, trying to minimise gas use, for the planet and the wallet.

    11PM: 15kW o'clock!



  • Registered Users Posts: 265 ✭✭ Conor20


    Yes - absolutely! Both for the fact that there is more wind generation relative to demand at night, and the fact that electricity is cheaper at night with a SmartMeter or a Day/Night meter (outside of the summer months when you have excess solar generation during the day of course, which is zero marginal cost to you). Energy Storage is the answer - whether it's a storage space heater, or a battery, or underfloor heating. We installed an 8kWh battery alongside the SolarPV system and we can also time that to charge through the SolarPV portal. We have it charge overnight for the winter months so it can power the house during the day. Looking at our most recent bill, the daytime electricity cost was €0.43 / kWh and the night time is €0.26 / kWh. We charge it with 8kWh and that plus the few kWh of solar we get each day in winter gets us most of the way through the day without touching the grid. Each day that saves 8 * (€0.43 - €0.26) * 6 months around winter * 30 days per month = €244.80 each year.

    On wind generation being relatively higher in Ireland at night, you're spot on. For anyone here, you can look at the real-time current energy makeup in Ireland at https://www.smartgriddashboard.com/#all . Because demand is higher during the day, on average wind will be a higher percentage of generation at night, and sometimes it is curtailed when there is too much, so if you can move as much of your demand - charging your car, charging a battery, charging a storage heater, etc - to the night time, it will be both cheaper for you, facilitate more wind energy on the grid, and make electricity cheaper for everyone overall. It's also good in that it minimizes the amount of gas that needs to be burned to power the grid, which is obviously a useful contribution in the present gas constrained situation.

    What I like about having energy storage is it gives you a way, if you want to, of optimizing your energy costs. We continue to have fun looking for ways to do this to save more energy and money. If you remember, the last week in September was unusually warm and sunny this year. Anticipating cold temperatures and high energy prices over the winter, we decided to use the abundance of Solar generation that week to turn on the heating function of the Heat Pump and start storing lots of heat energy into the floor of the house via the underfloor heating. Underfloor heating, if you remember from photos of our install (I'll paste one below), are simply pipes connected to the hot water heating system which run through the concrete under the floor:


    The concrete is 20cm-30cm thick and covers the 65 odd square meters of the ground floor. The concrete is essentially a very large thermal mass under the house. It takes lots of heat energy to heat up to room temperature, but once it's warm, it stays warm for a long, long time. Think of it like the titanic - it takes a huge amount of energy to get it going, but once it's going, it takes miles and miles to stop it. While underfloor heating isn't essential to switch to a heat pump (I know two houses who have recently switched over to heat pumps without underfloor heating and they are warm and toasty), it is slightly more efficient with a heat pump and keeps the house at a very consistent temperature. Long story short, that week, we turned 100kWh of SolarPV, run through the heatpump at a COP of 4 because it was 19C outside, into 400kWh of heat energy stored into the concrete and tiles of the floor area of the house. The floor, and as a result the house, has been nice and warm since with minimal additional heating. We basically blunted the heating costs for the house for the first part of the winter with a week of solar generation in September. 



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